I would say this game is not for you, but in case you want to keep with it:
First, the game can be a bit complex , overwhelming, and maybe even obtuse to a new player, but if i remember correctly, the game introduces all the systems gradually, so ignore them until the game tells you about them.
Second, this game is not dragon dogma, at all. Monster hunter is about managing your resources and positioning yourself carefully between actions when you battle each enemy.
Now, to answer some of your questions.
Dragonzdogma said:
Can I beat the game by simply selling all the junk I pick up and defeat the last boss with weapons I buy- I really don't feel like crafting and getting into the loot system and all this.
No, you cant.
Crafting is one of the core pillars of this game: you beat monster, carve monster, craft weapon/armor of said monster to beat new monsters. If you are missing an item, you go back to kill said monster another time until you get it (it may require for you to break/cut an specific part of the monster, or just carve some items on the map, like bones or cristals).
But it is not necessary to focus on this at the beginning tho: I would recommend you to try every weapon first (you have one of each type in the chest at the training stage), and once you find one that you think you may like (or controls similar to another game that you've played), start beating the first monsters with it. You can access the training stage if you speak to the cat that is in your room.
Once you have problems with one monster, try to create a new weapon / create new armor with any items you have (if doesnt matter if the armor parts are from different monsters or what skills they give you for now).
That should be more than enough for low rank.
Dragonzdogma said:
Why is my potion assigned to square - I was hoping that was my attack button, anyway to change this?
I have to constantly sharpen my blade with a soap stone - holding R stick and selecting it but Im not sure how I'm really selecting this.
I dont think there is, unless you change it thought the ps4 accesibility options.
The weapons have durability: when they are less sharp, they do less damage among other things. To select the sharpen stone quickly without using the regular items list, you have to press L1 (to activate the radial menu) + press up and release the right analog. The radial menu can be customised with whatever actions you want (craft items, use items, gestures...).
Dragonzdogma said:
Is my Cat a pawn like NPC - Can I make him pick up crap for me- cause I'm not liking how slow these animations are just to loot and loot, is border line red dead redemption.
Your cat will pick stuff for you at random, sometimes. You cant control him until much later, and even then you will only be able to give him two (now three) commands. The rest of the time he will do whatever it wants, and of course, draw the attention of the monster so you have some moments of respite.
Dragonzdogma said:
The game loot system is overwhelming and slow to pick up items- And there is this annoying timer (10 seconds) to pick up all the loot after I beat the boss, which does not allow me to pick up anything and boots me out from the quest quick.
Usually you have more time than that, which is more than enough to (and only to) carve the monster you just beat (and maybe some close items if you have any remaining time after carving the monster).
To pick stuff on the map, do it when you are not fighting or just go on an expedition.