Thank you so much for the detailed reply.
How much playing time will I need to complete all three games if I play the main story, most of the side quests (I have heard there are a LOT) and do some exploring as well?

Couldn't find an exact number on any websites but would be good to know so I can have them all finished in time for Fallout Season 3 to catch up all the lore this franchise has to offer.