Perfect elaboration ^ ^ ^ right there.
As far as the original questions posed by the OP: (my responses are in red below)
1) Are vendors allowing their snakes to be handled during these strange times? I’m sure my son will want some.
Up to each individual to set limits as they see fit.
2) Is frozen prey a better deal at shows or online?
Could go either way- do price comparisons ahead of time & take a calculator, or factor in the convenience of taking it home -but be sure to take an ice chest to keep it frozen!
3) Is additional foliage necessary in an aquarium? IE, tree branch, palm leaves etc. My son thinks it looks cool.
No, it does look nice & provides additional privacy for the snake as well as traction, but it also adds more places to trap fecal contamination & pathogens- one more thing to clean.My personal preference is to use branches for climbing/exercise but not foliage- but keep in mind I keep mostly rat snakes that love to climb & aren't shy like BPs- so take into account what you're keeping & their needs.
4) How to prepare for the 5+ hour trip home? Plastic container with clean towel and a hand warmer or two?
Personally I only transport snakes in a secured cloth bag, & that bag is placed in a padded ice chest or thick styro-foam box to protect from temperatures that are less than ideal.
Just a regular plastic container offers NO insulation to retain the warmth, even if you have a "hand warmer" for heat.
This also provides padding (protection!) in the event your vehicle has to stop fast, & reduces their stress from excessive handling etc.
Heat packs are a very good idea- plan for the unexpected, especially in winter. Vehicles can break down, or accidents can happen that tie up traffic, making your trip much longer than you planned.