let the ex housemates nominate mid next week?
 

invite them all back just to deliver one nomination each face to face
and give them all a chance for 1 act of revenge and to scupper the hopes of their biggest enemy just days before the final:devil:

No no no! Keep the evicted ones O-U-T!

I think that's an excellent idea and may be one of the last big twists as the game draws to a close.

The Sunday episode of BBBOTS hinted that Callum may somehow find his way back near the house, so...

oh there faces would be funny

That is better than family and friends nominating. However if there is another set of nominations it should be the housemates nominating. They have literally nominated in a normal way only 4 or 5 times this season.

^ "Secrets And Lies... secrets and lies..."

It's not meant to be a typical series.