Snapchat isn't on windows 10 mobile. And it probably won't come because the owner of snapchat hates indians, poor people AND windows, lol.
Fortunately there are lots of alternatives, and snapchat is mainly just popular in America. Its pretty small globally.
Instagram has stories, and face filters are coming soon to win10 mobile - probably android etc already has that - all those silly dog ears and stuff. It has a direct chat feature.
Whatsapp is also has a stories feature (and is encrypted too), for the privacy minded. Both those can be temporary/deleted in the story features I believe.
Skype is also a very popular messanging platform with, like those other two, around 500 millions users - lots of people use all of these. And there are probably a host more of those types of things that are cross-platform.
Just get your mates to use one of those, and ask for them to meet you in the middle on it.
Say "Hey I'm on a windows phone and it doesn't have the app, could we use another platform, are any of WhatsApp, viber, Instagram, skype okay? I'm open to suggestions..." (there are likely many others)
If they won't they ain't very good friends TBH. Friends meet friends in the middle, do what works for everyone. And because you can really do all the same stuff more or less elsewhere, its no drama.