mealybug treatment questions

[lobotomizedgoat]

Discovered mealybugs on three of my paphs today. I wiped off what I could with isopropyl but many were hiding out of reach in the crown and crevices between the leaves. I think I got some of those by dripping some alcohol in then rinsed them thoroughly, but I know there are still some hiding because they keep popping out here and there.

My goal is to find an imidacloprid product tomorrow, but I'm curious what other pesticides are effective (and safe for indoor use) in case I cannot find the good stuff where I live.

I'm also curious which treatments should be kept off the roots. I've seen various solutions of horticultural oils, soap, and alcohol mentioned but I don't have a good sense of what is OK to use on both foliage and media.

Lastly, while I only found three affected plants I'm guessing it's best to apply treatment to all the plants in the grow area just in case?