As for my personal opinion: If possible, remove the Tetramorium caespitum pupae and simply don't try to boost your colony.

There are many many different opinions regarding boosting ant colonies, but a good deal of keeping ants is about patience...
Especially with different kinds it's a very tricky thing trying to boost them. Sometimes works out fine, yet often fails... I don't think it will do any difference, if you try with another colony, as the pupae were accepted first, until they hatched....