Without having the names of your adons we are not able to tell if they could or could not work properly.
A general answer would be. Some will, others wont
KNown problems are chat related addons as Zos changed the chat to use a new chat proxy. Addons are not able to format the chat texts properly at the moment but I hope wil lfix this until PTS goes live.
I'm not aware of other mayjor problems on PTS so I guess the answer will be: We will see.
Some authors also test on PTS and fix the addons, or already created updates available working on live&PTS.