Mealybug treatment questions for effectiveness and to prevent re-infestation

[The Peloric Orchid]

I just discovered a few adult mealybugs on some orchids I was quarantining. What I have done so far is spray them one of those organic sprays full of essential oils and neem oil as a first step, but I know I need to do more. To that end, I have many questions about treatment plans.

1) If I go for a low tech approach and dunk my plants in a soapy water for a few hours, should I try to dunk all my plans at once (such as in a plastic tote)? If I do so in batches, do make a fresh soap solution each time? How often should I follow up with another soapy bath?

2) If I decide to spray and drench the medium as my treatment option, should I repot the plants before starting, after the last treatment, or both?

3) For whatever treatment I decide, I'm assuming I treat all the plants in the quarantine room, not just affected plants and their closest neighbors?

4) I've seen estación seca and others write that treating plants doesn't do anything about the eggs in or around the quarantine area. What should I do about that? Vacuum?