re: Anybody have any experience evicting a colony of BATS from a house?

I think you'll want to wait until after the breeding season, or, you'll have a bunch of adult bats trying like hell to get back to the young. Sets up a bad scene.

My in-laws inherited a place that had the largest residential infestation the bat guy had ever seen. 15,000 bats, 3 different species. They had to wait until after the breeding season to put the one-way check valves on the exit points and close up every possible opening. They can squeeze in any spot/hole the size of your finger. It cost a bunch for the in-laws, maybe $10k-ish. And as soon as they evicted the 15k bats, the bat guy was getting dozens of calls in the next few weeks from people and business where they moved in. Not a bad business model, chasing the same bats all over the county.