How to get the following skins -
Archetype - item shop (wait for rotation)
Battle hound - item shop (wait for rotation)
Growler - item shop (wait for rotation)
Jaeger - item shop (wait for rotation)
How do you earn v bucks besides paying? - if you have save the world, you can fill out the collection book, and collect the daily rewards for small vbuck amounts
I noticed my first game was 20vs20 but I thought the game was 100 players and everyone against everyone? - most likely scenario is that you selected a limited time mode rather than the SOLO mode
Are there different maps or just the one for battle royale? - there is just one map, but it is ever changing each season with new things being destroyed/removed/added/changed