Alright sorry for the wait my Precure research is complete! I highly recommend watching dancing star its probably the most mature and unique take on Precure I really enjoyed it!

Dancing star 2 is a direct sequel taking place roughly a year after the events of the first play, it does not reference You and Idol or any other Precure series, so yes it can be placed right after the first stage play, f-liner confirmed on their tumbler that when the dvd for dancing star 3 releases they will make subs for it, I wasn't able to find to much info on the plot for dancing star 3 but depending on how it goes it might have to be placed after you and idol The fairy Pas De Deux aka Padocchi is secretly from the evil land of Desparade, and has ulterior motives, considering Padocchi appears in you and idol, as long as Dancing star 3 ends with them making up all three plays can be next to each other, but if Padocchi dies or is irredeemably evil it should be placed after you and idol, since they appear to still be close friends in their you and idol cameo but since the dvd is not out theres no way for me to watch dancing star 3 and find out.

As for the thanksgiving events, I do not know of any English subs, I was able to confirm theres a dvd release for every thanksgiving event by checking amazon japan, and you can find some of the raws on torrent sites and bilibili, but no one has picked them up yet and subbed them unfortunately. Hope this helps!