Common workflow for tape based 24p posting in the PAL world is to set the deck to 25fps playback and also (separate setting!) to 24->25TC conversion. Then capture into a PAL 24p project. Picture will be slowed down, and any 24 or 25TC based EDL can be generated, since you can copy-convert the Start TC (25TC) into the TC24 column and it will calculate back to the original 24TC. My very first HDCAM 24p project was done this way, and finished in Avid DS. I don’t think there were any issues, except for some motion effects that did not translate well back in those days (but this was 2003 or 2004 or so).
You have to wonder about sound, though. It’s usually a better idea to work double system, but if you do need to use the sound from the tapes, you need to figure out a way to do that, without compromising the sound quality.