Like the topic title says...how many each of the regular and elite jawas can you field in the campaign mode of the game? Just one of each?

One each.

Jawa Scavenger said:

In a campaign, players are limited to the number of Deployment
cards included in this expansion. Therefore, the Imperial player
is limited to one regular and one elite Jawa Scavenger group,
regardless of how many copies of this expansion he owns.

If you buy the Jawa pack, it only comes with one plastic figure - but two cards (regular and elite). Does the pack also include a cardboard token? Otherwise how do you deploy two Jawas? Given that there is only one figure, it seems like you have to buy two separate packs to use the cards you get in one. That seems kind of unfortunate.

The packs do not usually come with any tokens. Additional cardboard for just one token would add to the cost nonproportionally to the benefit.

You can use a proxy figure (you may have one from some other game or toy line), or a proxy token. I have previously modded the other sides of the rebel trooper tokens to have some other figures.