Can use any weapon for Safi pretty easily yeah, although some are worse than others(SnS can't reach most stuff besides legs, bow can't reach wings, it's harder to get consistent head hits with hammer/HH and such).
For bow I'd recommend hitting the head, bow can easily weave left and right dodging attacks when you have aggro, while still outputting full damage on the head. That's what I do when I'm done breaking wings with LBG, can use the sliding reloads to dodge stuff and honestly most attacks are pretty easy to avoid. It might be harder to gear properly for the grabs with bow however since 4pc silverlos is so restrictive, on my LBG build I have health boost 3 AND divine blessing 5 and also 20+ fire res(via decos, could use food instead though if needed) so basically if I get grabbed even if everyone else is sleeping I won't die. Might be worth running a lower damage build with normal crit ele, especially since you kinda want partbreaker 3 anyway and you can't fit that in standard bow builds. Normal crit ele with partbreaker is a lot better than true crit ele for this I think.
Generally I wouldn't focus legs at all unless that's the only thing left. If using slashing weapons you want to go tail first, if using guns you want to shoot wings first(and back to make it easier to break), if using other stuff you should focus head. The wings at 50points each, the tail is 140 points or something iirc, the back is 100points(easy to break with ranged and mounts) and the head is 200 for the 2 breaks, and the chest is like 120 but can only break during phase 3. Meanwhile legs are 20 each, so pretty much any other parts(assuming you count wings as one part, they're easy to break both solo) is more points than all 4 legs together, and legs aren't even easy to break they're pretty tough. So even with shittier HZV it's better to focus the head imo.