It seems that I have been stuck on about two things in this game, and I need a bit of help over here. First thing: How do I interact with birthdays and special calendar days? I have been trying to give gifts on birthdays to the celebrated person and on special days like egg day I don't find anything to trigger the event no matter what I do. The second thing that I can't figure out is the threesome/harem things. I have no idea how to make those stuff happen.

No, I did not. In the phone app it still shows on the counter that there are more content.

I keep on giving gifts for everyone, but for some reason Linora and Willow is not making advancement in their stories. I do have the three stars when I check in the phone contacts app, but it is not triggering anything. Do I have to keep on giving them gifts, or did I run into a bug

yeah, i had the same question. the asnwer is yes, if you buy a game once, you can download the newer versions for completely free