I'd like to clarify how many suppression tokens you allocate from multiple weapons within the same unit.e.g.

Troopers with blasters and heavy weapon - can they fore each group of weapons separately and therefore potentially give 2 tokens?

AT-ST using Arsenal 2 are these 2 separate attacks and therefore can allocate 2 tokens?

Except you roll all dice from attack at a unit at the same time. So the AT-ST firing 2 weapons will have those weapons polled into a single dice pool. And then you only get one suppression token from that attack unless the weapon has suppressive X.

Look at step 2B of the attack process in the RR.

DarkTemplars is correct. I find your questions slightly vague, as you're asking about how many tokens you give rather than what a defender is taking. It is possible in both of your examples for you to fire those weapons at different targets , in which case each target would be eligible to take suppression. However, if you're talking about firing at one target using multiple weapons, DarkTemplar covered that.