>>11236639I lived in a similar environment a couple years back. Old fashioned wooden rent attic crawling with termites and enough humidity to turn white page books into antiques in a year so dust wasn't just the issue. Fixes I made included buying a glass display that wasn't completely airtight but it helped block dust, along with the decision to simply keep my other figures in their boxes until I moved into a larger space.
Q1: Yep, it'll be good enough that any dust that comes in won't lodge inside those tiny crevices in your toys like say mechs and robots.
Q2: Don't use open shelves. You're pretty much forced to use either your old nan's fine china display cabinets or nothing.
Q3: Yes but not so much compared to open shelves. Basically, they have about as much protection as your average kitchen cabinet. Expect to clean them maybe three times a year. Do compare that to open shelves where the dust accumulates in less than a month.
