I dont know the extra costs involved with running a 4th car instead of just 3, but if Toyota aren't going to be paying a huge salary to keep Tanak/pay Ogier, they could have extra budget needed to run 4cars and sign someone like Mikkelsen (who will be happy to drive for a relatively small salary in WRC terms vs paying for a seat at Msport - which seems to be his only other option).

Latvala, Meeke and Mikkelsen would be a nice 3 car team given what's left available, and then you can run Kalle for a full season pressure free in a 4th car. Don't know what Tanak will have been demanding, but I'm sure it'll have been anywhere between €5-10m a year, which is a lot.