I’d stick with Tanganga, very disappointing season for him but with a dominant CB partner he has shown he can be class at this level (albeit with Millwall and sadly not so far with us).
McGuinness is the archetypal ‘head it, kick it’ defender, and whilst I think he has occasionally looked ok for us, he mostly looks like he’s playing above his level, which is probably L1.
We got Bindon on loan last season and after a shaky start he definitely found his feet, I’d not necessarily be against trying to get him back again or alternatively using a loan on another premier league CB - we’ve been hit and miss with loans but there are definitely gems out there that can set us up for the season - Souttar last year for example.