Hello, thanks for the questions, glad you like the assets!
1. Yes, once you purchase these future updates are locked in for the packs purchased
2. Not unless you purchase new expansions (currently itch doesn't support this kind of bundle sale, so these are priced and designed with that in mind).
3. No real difference, itch will get updates faster. At the moment the Patreon store is more of an experiment for me.
As for the other questions, yes a basic dying animation exists, but it is more of a disintegrate animation. Hit animation is a flash to white, death is a flash to white with pixels being removed over frames.
For the character animation questions, yes, this is something I can add. However I'm about to start doing some major updates on all the packs in this series, including a new character design (and probably some reworks on the old one). Some basic character previews will likely be included once I get to this huge list of updates for the series!
Cheers!