Welcome!
1. Yes, some people grow their bananas in 15-30 gallon pots and they manage to do okay and fruit. Your bunches are likely to be smaller than a comparable plant in the ground which would have a much larger root system.
2. Unless you are growing a seeded variety, you don't need to worry about pollination. Even seeded varieties have both male and female flowers. On the edible bananas the tiny male flowers will show up after the female flowers which become fruits.
There are many sources for buying banana plants. Unfortunately, many of them mislabel their plants or don't know what they have. You might want to order from
Catalog of banana plants offered at Going Bananas,
ENCANTO FARMS NURSERY, and/or
Northern Tropics: Home as they are reliable sources and all are members here. I suggest you considered adding Dwarf Brazilian and Dwarf Namwah to your collection. How tall is your hoophouse?
Good luck!
Harvey