gmail, contact, calendar should have no problem... but chrome, keep and other services you have to change as well. Not sure if dropbox is available on this. But I've been using OneDrive, OneNote, DropBox and Google Drive since Android so it's not much of a problem for me when it comes to cloud storage.

Browser, had to change to IE. I do find few alternative browsers, tried Maxthon but IE is much better IMO. IE is capable, but not sure about the fast when compete against chrome on Android. I don't exactly mind, I find it just ok but for me Chrome is more streamlined in the interface design compared to IE on WP. takes some time to get used to.

Whatsapp, FB, Instagram is there. Pinterest just came in with beta as well but I don't think flipboard is available (not sure why, I can recall flipboard is available as Win8 Store Apps). Camera edit, I use built in feature. Not sure how that is compared to snapseed but I find it enough for cropping, reframe; that's all I'm willing to do on mobile phone...

If you rely too heavily on Google's services, probably you want to stick with Android unless you are willing to migrate.