1) On the desktop version, you can use the shortcut key # to delete a thread. No related shortcut on the mobile versions that I know of.
2) You can snooze a thread not only a day/time (Wed 3pm), but also a place (Home, Work, local Costco); it'll resurface on your phone when you are present at that location.

Disclaimer: I work at Google, but don't work on Inbox or Gmail (I actually work on Google Flight Search, which is a bit more aligned w/ Flyertalk )