Microsoft doesn't have to many first party developers so it would make sense for a them to buy them and they have already put a lot of money into making TF exclusive.
Very unlikely. Phil Spencer has stated that Microsoft is interested in investing in new IPs, rather than buying out studios.
Microsoft is more likely to do a deal with EA / Respawn to keep the TitanFall franchise as an exclusive in the future, regardless of the preferences Vince indicated on twitter.