This is all information I've gathered from the FIFA 15 Starhead Thread on EA's forums.
Teams with partnerships still needing scans: Sevilla, Real Betis, Real Madrid, AS Monaco
IMO the only teams that can definitively be confirmed as being scanned for FIFA 15 are Southampton and Tottenham. Jose Fonte, Rickie Lambert, Morgan Schneiderlin and Artur Boruc have been seen with brand new starheads:
Additionally, Moussa Dembele, Christian Eriksen and Emmanuel Adebayor look like they have received updates.
Obviously there have been other rumoured scans/rescans, such as Roma and Napoli due to EA's official Serie A licensing press release and the two teams being featured in the hype trailers. Eden Hazard is strong evidence Chelsea was rescanned (you can just barely see the 18 cams around him):
Same for Lukaku and Everton:
One could just be the Belgian coverstar though.
Beyond that, Mignolet and Sterling have been seen with new faces as well, but I'm not sure Liverpool have been rescanned because they might just be including the scans that they took last year but omitted from FIFA 14.