you still have to state how you 'swim' in the air, if not mojang is not gonna fix that
This may be intentional. Because you are suffocating, its maybe the same reason for you are drowning. The code may be: if player is in block, oxygen bar appear. since water is technically a block, it will appear.
I think is a block conversion error, it tells you that java version needs to be updated first and then you move to bedrock, not sure but i think so.
if you dont allow mob drops in your minecraft world, it will be like that. not a bug.
Here it is: Chiseled Plastic Texture Pack (its mine btw): https://www.mediafire.com/file/26oe81yw5zmedwb/CPTP_1.3%252B.zip/file
I have checked with the unmodified files and found out that the empty armor slots and MAYBE the leather armor is my fault. However the elytra, clock and compass textures seem to not appear despite the name of each texture is correct and the texture pack is enabled. I might also try making a pack that fixes this issue.