I do have a bit more to go over with you, though.
One: Don't think about this in terms of a MOBA. Servants aren't designed with "kits," everything you put on them should have some connection to who they are and what they did. For example, did Hayha actually use remotely detonated charges? Seeing as I'm not certain that any sort of radio-detonated explosive was even invented at that time, I'd be inclined to say "no." So he shouldn't have that as a Noble Phantasm. Additionally, as I already noted, Camouflage is a personal skill. That together with Presence Concealment easily covers his ability to remain undetected. Going along with the idea of not having a kit, if his last bullet does more damage, it should be for an actual reason, and not because you're basing it on a skill from a video game. As a minor note, his rifle held five rounds, not four.
Before you ask, Rusty, Class Skills are listed in with the rest of them, even if they're on the "incorrect" class. Astolfo's profile lists his Independent Action right below his Riding skill.