1) Yes, initially all of my snakes (corns, milks, balls) were in display cages/terrariums for years before I ramped up my collection and succumbed to the 'evil' rack systems (which are actually quite nice to work with). I used maternal incubation in the beginning-my displays were poorly designed for egg incubation and viability reflected this...
2) Currently I mate my snakes and clean their enclosures on a regular schedule right up until the eggs are obvious-never had any issues. I would not deliberately handle my girls while they were building eggs though: That seems like a recipe for disaster.
I still have display cages. But, I do not rotate any of my females through them during the breeding months.