which glue would be teh strongest to glue dio buildings made of plaster such as those by Linden

I would use either ordinary white glue or tilegrout - the tile grout have the advantage that you can use it to fix/hide the assembly.

I would allso drill some small holes trough the assembly and reinforce it with some wire.

jan is right. For reinforcement you could use toothpicks too.

I've used the Gel type CA glues on plaster with no real problems.

my last building i used ca glue and it was fine

I use Aleenes thick tacky glue for all my plaster. Very thick and wont run. Find it very tough and durable too. Put enougjh to cover joint and let dry. Cleans up easy but try not to get any outside off joint so you can fill in joint with plaster and scribe stone or brick work to match original.