I too am on iCloud, also have all my passwords, bookmarks, even photos synced. For example, one thing I do right now is post photos on my instagram account, because the way Instagram works, you can only upload from a mobile device, I drag an drop my photo into iPhoto, which automatically appears in my Photo in the phone instantly. Then I upload to Instagram.
I have to figure out how I can do a similar thing to an Android Phone…from my iMac.
I also have to figure out may be how to use Google Drive or Dropbox in place of iCloud. I have a 1TB storage on Dropbox so in that regard, cloud storage I am sorted.
Music I just use Amazon Prime Music so no problem there. iMessage I wouldn't know because I don't text that much, can possibly replace it with WhatsApp and Facebook Messenger.
The Plus thing with the phone I just ordered uses basically a stock Android OS so minimal bloat.