Lots of mosquitoes where I live too, but the trick is to keep them outside. How are they getting in? (no screens on windows? fix that...)
Is there any standing water where they can breed? (unused toilet or other? fix that...)
I agree about the topical repellents, kinda yucka to use on your skin & clothes, but I've never used any of the room-diffuser kinds, as I don't have
any mosquitoes in the house. If I think of anything, I'll get back to you...I hate mosquitoes & I'm glad you're thinking about what is safe for snakes too.