3) can you have multiple accounts to farm things like gobs?
I think you can do that. You can even connect your main account with alt accounts. Some activities are blocked for alts of the same IP or something, but minigames and dailies should be accessible I think...
As the dev wrote - you can have 5 accounts. The restrictions usually involve only PvP activities like SW, 1vs1, 3vs3 and so on (as far as I know and I have tested) - you get no rewards with any of your characters if they are in the same PvP zone at the same time. I have 2 accounts only, not full, and I farm goblin with them every day.
I personally see no point in having more than 2 accounts. I would recommend having 2 accounts in these cases:
1) fake party - VERY useful when you are doing the mirror world inis with your main character
2) your main character has a long crafting queue and you want to do something meanwhile
3) to powerlevel one of the classes of your main character by using an alt