How do I get Google+'s notifications into Android's notification list?
Uhhh...I get Google+ Notifications all of the time.

Check:


Settings | Apps | Google+ | Show Notifications is checked
In the Google+ app, Overflow menu (three vertical dots) | Settings | Notifications is ON. Tap that entry and choose which types of notifications to get. I see

POSTS AND MENTIONS

Mentions
Shares
Comments
Comments on a post after I commented
Circle subscriptions

CIRCLES

Adds me

PHOTOS

Tags me
Comments on a photo I am tagged in
Comments on a photo I tagged
Photos added from Instant Upload

EVENTS

Invitations or updates to events
Reminders about events I'm invited to
Activity on events I created

COMMUNITIES

Invites me to a Community