(1) GraphQL returns only what the client asks for. No need to worry that adding to an existing resource will increase response times or bloat the response for existing queries.

(2) If you decide to go the friendsandfamily route, you'll just be adding `family`. You won't have `friends` endpoint and `family` endpoint and `friendsandfamily` endpoint. A GraphQL schema doesn't increase combinatorially in size; rather the possible compositions increase combinatorially.

for 2) isn't this the same as adding an optional "include=family" to the existing friends endpoint?

This is what the JSONAPI spec suggest too.

Yep. You can use query parameters to fix 1) and 2).

Go down the rabbit hole a little bit further, and you have GraphQL (if you're lucky....if not, you'll just have a mess).