Just in case OP is susceptible to peer pressure, I want to offer that if you really love her, it’s OK if you have different operating systems on your phones.

Haha yeah I couldn't care less, I just thought it was a funny anecdote and it's probably not entirely just because of the color, that's just what she said when I asked her about it a couple years ago. And excluding me from the group chats and having her relay everything to/from me is probably for the best anyways, I'm terrible at checking my texts and my friend/family know the fastest way to get a hold of me if Im not replying is to text her instead :p.

It's really absurd that this has to be stated in writing! If a "friend" would cut you out of a portion of their life because of something as trivial as what smartphone messaging platform you use, well, I have some bad news for you...

Shared calendars are a thing with Google and sync with any device, desktops included. Shopping lists are shared on Amazon and most grocery store apps.

They're also cumbersome.

In what way? o-O

Google Calendars has sub-par iCal/vCal support, and will omit calendar entry information (or entire entries) sometimes.

It deals with sharing pretty well when both parties have Google Calendar accounts.

The same goes for Google - you can share Keep lists and Google Calendars, all for free and easy.