I think when the discord link was posted here it was for a short time. The main way of joining would be through the substar membership. Not sure how to join now though.
It looks like the files being released will continue to be 'updates' given their prospective sizes. it's probably best to keep all separate files and make a master file with the copies.
I think you're confusing the scenes being so good they don't require animation, and the dev's ability to create animated scenes. there are tons of excellent Japanese VN's that don't have animation. Idk, I guess it's down to personal preference.
I for one really like it.
if you mean the haunted house then they will be (hopefully) in the next update. If you mean the escape room, you are required to play through the game again (save at the start) and the person who helps you (at least once) most will phone you during the leya/luna/lola visit