I (also) always use Melissa in conjunction with Zeri.
Sometimes they're the only two I deploy on a particular (area of a) map. They get a feel for it, kill whoever they bump into and assess any other units I may need in that situation. Solves the problem of not using her around other females and I often trigger Zeri Lover.
I haven't used Squad 7 members (cause I'm afraid I'll simply favor them so much I won't use VC2 characters) so I can't say for sure but I'm willing to bet overall favorite Sniper would be Marina if I used her - she was my favorite Sniper in VC1 (and cool looking).
I made Melissa sniper. She is one of the most accurate.
Lotte has high accuracy too but I think she is better as scout vet because her unlocked potential gives her a chance to move again, so all her AP is replenished. Really great if you're trying to do a scout rush to cap that camp on the other side of the map.
Marina also has high accuracy but she can't really hide in grass because of her potential. I think snipers need to be able to hide in grass because they're pretty squishy.
No, snipers crouch in camp so you can standby them for 0 cp... unlike in VC 1 because you can only deploy 6 units and it is better to end turn with units that have suppression fire. They are easily killed too compared to troopers especially if you play against human player. In versus mode the only way to use snipers are to shoot and standby anyway.
Anyway Marina simply owns with her "good night", "sweet dreams", "I'm too far alone" remarks.
Actually Nichol had the least HP, least evade, least defense than all scouts, so he's the worst scout in the game. This is according to the VC2 freshman cadet guide. His aim is worse than melissa/lotte/chloe as well.
he has evasion boosts and night vision... Tender Emotions give him bonus vs both armored stuff and infantry... plus even if hit, he has full hp recover =) both his health and shoot are better then Melissa's... so he IS the best sniper... though yes, maybe not that good scout =)
No his hp and aim is lower than melissa (snipers are subclass of scouts) according to the sega guide. His talent is pretty much on par with other scouts too. Night vision/nocturnal is one of the worse talent actually since it is very situational and did not raise damage/accuracy. Honestly speaking, among all the standard scouts, lotte makes the best sniper/scout because she can act twice using 1 CP. However she's ugly so I didnt use her lol.