Aside from Nintendo's first-party releases in Q1 2019, third-parties traditionally have a strong season in February/March in Japan. In 2013-2017, they were all PS exclusive, because the Wii U wasn't a viable platform. However, we see more and more PS4/PSV series go the PS4/NSW route. Take Digimon Survive for example (which is also a 2019 release btw). Obviously first-party games will take the lion's share of the sales, but if big third-party series come to Switch as well (especially the typical shonen series), they will definitely add to the busy/stuffed feeling of the release line-up.
Here's an overview of the sizable Q1 third-party releases by Japanese developers on PlayStation of the last couple of years:
2018
[PS4] Dissidia: Final Fantasy NT <ACT> (Square Enix) {2018.01.11} (¥7.800) - 105.667 / NEW <79,19%>
[PS4+PSV] Gintama Ranbu # <ACT> (Bandai Namco Games) {2018.01.18} (¥7.600) - 61.860 / NEW
[PS4] Monster Hunter: World # <ACT> (Capcom) {2018.01.26} (¥8.980) - 1.245.169 / NEW <92,07%>
[PS4] Dragon Ball FighterZ <FTG> (Bandai Namco Games) {2018.02.01} (¥7.600) - 68.731 / NEW <77,04%>
[PS4] Dynasty Warriors 9 # <ACT> (Koei Tecmo) {2018.02.08} (¥7.800) - 117.495 / NEW <70,59%>
[PS4] Sword Art Online: Fatal Bullet # <ACT> (Bandai Namco Games) {2018.02.08} (¥8.200) - 75.623 / NEW
[PS4+PSV] Seiken Densetsu 2: Secret of Mana # <RPG> (Square Enix) {2018.02.15} (¥4.800) - 53.989 / NEW
[PS4+PSV] Cyber Troopers Virtual-On x Toaru Majutsu no Index: Toaru Majutsu no Virtual-On # <ACT> (Sega) {2018.02.15} (¥7.990) -27.222 / NEW
[PS4] Girls und Panzer: Dream Tank Match # <ACT> (Bandai Namco Games) {2018.02.22} (¥7.600) - 46.411 / NEW <93,66%>
[PS4] Metal Gear Survive <ACT> (Konami) {2018.02.21} (¥4.980) - 31.359 / NEW
[PS4] Senran Kagura Burst Re:Newal # <ACT> (Marvelous) {2018.02.22} (¥6.980) - 24.118 / NEW
[PS4] Like the North Star # <ADV> (Sega) {2018.03.08} (¥8.390) - 123.116 / NEW
[PS4] Attack on Titan 2 # <ACT> (Koei Tecmo) {2018.03.15} (¥7.800) - 28.480 / NEW (also on Switch)
[PS4] Valkyria Chronicles 4 # <SLG> (Sega) {2018.03.21} (¥7.990) - 62.921 / NEW
[PS4] Ni no Kuni II: Revenant Kingdom # <RPG> (Level 5) {2018.03.23} (¥8.000) - 56.014 / NEW
[PS4] Super Robot Wars X # <SLG> (Bandai Namco Games) {2018.03.29} (¥8.600) - 143.301 / NEW
[PS4] Shining Resonance Refrain # <RPG> (Sega) {2018.03.29} (¥5.990) - 23.054 / NEW
2017
[PS4] Kingdom Hearts HD II.8 Final Chapter Prologue <RPG> (Square Enix) {2017.01.12} (¥6.800) - 137.797 / NEW <86,31%>
[PS4+PSV] Danganronpa V3: Killing Harmony # <ADV> (Spike Chunsoft) {2017.01.12} (¥6.400) - 116.172 / NEW
[PS4+PSV] Valkyria Revolution <RPG> (Sega) {2017.01.19} (¥7.990) - 56.416 / NEW
[PS4] Resident Evil 7: biohazard # <ADV> (Capcom) {2017.01.26} (¥7.990) - 187.306 / NEW <58,63%>
[PSV] Uta no Prince-Sama: Repeat Love # <ADV> (Broccoli) {2017.01.26} (¥5.800) - 29.008 / NEW
[PS4] Nioh <RPG> (Koei Tecmo) {2017.02.09} (¥7.800) - 75.477 / NEW <90,68%>
[PS4] Yonmegami Online: Cyber Dimension Neptune # <RPG> (Compile Heart) {2017.02.09} (¥7.200) - 42.508 / NEW <88,91%>
[PS4] NieR: Automata <RPG> (Square Enix) {2017.02.23} (¥7.800) - 198.542 / NEW <92,35%>
[PS4+PSV] Super Robot Wars V # <SLG> (Bandai Namco Games) {2017.02.23} (¥8.600) - 183.887 / NEW
[PS4] Tom Clancy's Ghost Recon: Wildlands <ACT> (Ubisoft) {2017.03.09} (¥8.400) - 89.791 / NEW <91,52%>
[PS4] Kingdom Hearts HD I.5 + II.5 ReMIX <RPG> (Square Enix) {2017.03.09} (¥6.800) - 62.770 / NEW
[PS4] Senran Kagura: Peach Beach Splash # <ACT> (Marvelous) {2017.03.16} (¥6.980) - 53.747 / NEW
[PS4+PSV] Accel World Vs. Sword Art Online: Millennium Twilight <RPG> (Bandai Namco Games) {2017.03.16} (¥6.800) - 70.669 / NEW
[PS4+PSV] Warriors Stars # <ACT> (Koei Tecmo) {2017.03.30} (¥7.800) - 58.234 / NEW
[PS4+PSV] Blue Reflection: Maboroshi ni Mau - Shoujo no Ken # <RPG> (Koei Tecmo) {2017.03.30} (¥7.800) - 48.442 / NEW
2016
[PS4+PSV+PS3] Odin Sphere: Leifthrasir <ACT> (Atlus) {2016.01.14} (¥7.980) - 95.428 / NEW
[PS4+PS3] Yakuza: Kiwami <ADV> (Sega) {2016.01.21} (¥6.490) - 163.683 / NEW
[PS4+PSV+PS3] Dragon Quest Builders: Alefgard o Fukkatsu Niseyo # <ADV> (Square Enix) {2016.01.28} (¥5.980) - 372.539 / NEW
[PSV] Uta no Prince-Sama: Music 3 # <ACT> (Broccoli) {2016.01.28} (¥3.800) - 51.289 / NEW
[PS4+PS3] Romance of the Three Kingdoms 13 # <SLG> (Koei Tecmo) {2016.01.28} (¥8.800) - 35.532 / NEW
[PS4] Naruto Shippuden: Ultimate Ninja Storm 4 <FTG> (Bandai Namco Games) {2016.02.04} (¥7.600) - 64.446 / NEW <74,86%>
[PSV] Kan Colle Kai # <SLG> (Kadokawa Games) {2016.02.18} (¥5.800) - 140.757 / NEW <80,17%>
[PS4+PSV+PS3] Attack on Titan # <ACT> (Koei Tecmo) {2016.02.18} (¥6.800) - 150.682 / NEW
[PS4] Street Fighter V # <FTG> (Capcom) {2016.02.18} (¥7.990) - 41.990 / NEW
[PS4] I Am Setsuna <RPG> (Square Enix) {2016.02.18} (¥4.800) - 61.623 / NEW
[PS4+PSV+PS3] Kamen Rider: Battride War Genesis # <ACT> (Bandai Namco Games) {2016.02.25} (¥7.200) - 77.778 / NEW
[PS4+PSV] Gundam Breaker 3 <ACT> (Bandai Namco Games) {2016.03.03} (¥6.800) - 141.219 / NEW
[PS4+PSV] Summon Night 6: Lost Borders # <SLG> (Bandai Namco Games) {2016.03.10} (¥6.800) - 56.826 / NEW
[PSV] Digimon World: Next Order <RPG> (Bandai Namco Games) {2016.03.17} (¥6.800) - 64.218 / NEW
[PS4] Dark Souls III <RPG> (From Software) {2016.03.24} (¥7.430) - 210.141 / NEW <82,51%>
[PSV] Hatsune Miku: Project Diva X <ACT> (Sega) {2016.03.24} (¥6.990) - 69.438 / NEW
[PS4+PSV] Dead or Alive Xtreme 3 # <SPT> (Koei Tecmo) {2016.03.24} (¥8.800) - 66.682 / NEW
[PS4+PSV+PS3] Nobunaga's Ambition: Sphere of Influence - Sengoku Risshiden # <SLG> (Koei Tecmo) {2016.03.24} (¥8.800) - 46.854 / NEW
[PS4] Star Ocean: Integrity and Faithlessness <RPG> (Square Enix) {2016.03.31} (¥7.980) - 113.022 / NEW
2015
[PS3] Tales of Zestiria <RPG> (Bandai Namco Games) {2015.01.22} (¥8.715) - 340.891 / NEW <89,52%>
[PS4+PS3] Dragon Ball: Xenoverse <FTG> (Bandai Namco Games) {2015.02.05} (¥7.690) - 78.911 / NEW
[PS4+PSV+PS3] Samurai Warriors 4-II # <ACT> (Koei Tecmo) {2015.02.11} (¥6.264) - 90.561 / NEW
[PS4+PSV] God Eater 2: Rage Burst <ACT> (Bandai Namco Games) {2015.02.19} (¥6.145) - 272.004 / NEW
[PS4+PS3] Dead or Alive 5: Last Round # <FTG> (Koei Tecmo) {2015.02.19} (¥7.344) - 35.728 / NEW
[PS4+PS3] Dragon Quest Heroes <RPG> (Square Enix) {2015.02.26} (¥7.344) - 594.749 / NEW
[PS4+PS3] Yakuza 0 <ADV> (Sega) {2015.03.12} (¥8.845) - 236.329 / NEW
[PSV] Digimon Story: Cyber Sleuth <RPG> (Bandai Namco Games) {2015.03.12} (¥7.171) - 76.760 / NEW <91,41%>
[PSP] Uta no Prince-Sama: All Star After Secret # <ADV> (Broccoli) {2015.03.12} (¥6.264) - 67.237 / NEW
[PS4] Final Fantasy Type-0 HD # <RPG> (Square Enix) {2015.03.19} (¥7.344) - 92.094 / NEW <59,59%>
[PS4+PS3] Resident Evil: Revelations 2 <ADV> (Capcom) {2015.03.19} (¥5.389) - 115.731 / NEW
[PSV] Minecraft: PlayStation Vita Edition <ADV> (Sony Computer Entertainment) {2015.03.19} (¥2.592) - 36.151 / NEW
[PS4+PSV] Sword Art Online: Lost Song # <RPG> (Bandai Namco Games) {2015.03.26} (¥6.664) - 194.388 / NEW
[PS4+PSV+PS3] One Piece: Pirate Warriors 3 <ACT> (Bandai Namco Games) {2015.03.26} (¥8.424) - 198.363 / NEW
[PSV+PS3] Pro Baseball Spirits 2015 <SPT> (Konami) {2015.03.26} (¥8.208) - 108.523 / NEW
[PS4+PSV] Senran Kagura Estival Versus # <ACT> (Marvelous) {2015.03.26} (¥7.538) - 74.795 / NEW
[PS4] Disgaea 5: Alliance of Vengeance # <SLG> (Nippon Ichi Software) {2015.03.26} (¥7.776) - 22.725 / NEW
While the Switch can't expect all of the PS support to come over, I think a lot of licensed content, like Super Robot Taisen, Sword Art Online, Gundam, Digimon, Dragon Ball, One Piece, Naruto, etc, has a good chance of coming over. Koei Tecmo almost always releases one or more new Musou game in Q1; 2015 and 2016 had new Digimon games (and 2017 had a PS4 port), so I wouldn't be surprised if Survive is a March game; there's a new Super Robot Taisen game every year; a lot of anime licenses show up every year again - those were on 3DS in 2015/2016 and went UE4 in 2018.