The last stairs in the building of celadon city is accessible?
Try to be more specific, please. There's a lot of buildings and stairs inside Celadon City.
The Relic Beast and Lake Monster chapters require Rock Smash which isn't obtainable yet, so no, those aren't completable.
I knew that Buried Alive was in this ROM Hack, but this is the first time I hear that it's somehow obtainable in Beta 13 Part 1.
For a list of the currently completable side quests,
there's this guide.
Already reported. Remember to save before any important battle and well.. avoid losing them.
1) The Kangaskhan Village isn't crashing with the latest patches applied, so most likely that's your issue.
2) Already reported.
3) Already reported. Don't go any further than the interaction with Bulbasaur at the entrance of Route 1 or you'll lose the Running Shoes.
4) Beta 13 Part 1 ends after getting the Volcano Badge from Blaine. After that you can:
-Defeat the trainers in Route 29
-Grind for the Beta 13 Part 2
-Catch the pokémon that you haven't caught yet.
-Revisit Kanto now that you have Cut and Surf.
-Get all the TMs that you haven't obtained yet.
-Complete the available Side Quests that you might have missed.