Red Green Blue would have a majority according to my amateur calculations, in which the greens get a combined 11 seats. You probably know as much about this as I do, but the Green parties were blamed for all kinds of things at the end of the first 'purple' Verhofstadt cabinet, of which they were part. Ecolo ended up stepping out of the coalition just before the end, and the Flemish green party did not meet the threshold at the last federal elections. So they're probably not jumping to join the same coalition again.

However, there is plenty of animosity to go all around in Belgian politics.

The thing is that if the Christian Democrats become the largest party combined, it is highly probable that they will be able to make the first steps towards forming a coalition. If their attempts fail, all bets (save on the far right, which remains in its cordon sanitaire) are off.