Gadgets questions

Have created a hero that primarily uses Gadgets, and wanted to clarify a few things - the books are surprisingly unclear about everything that can be done with them, and... oi. They can be surprisingly gamebreaking if not handled correctly.

Character has 3 primary Gadgets, all with the 'Arsenal' extra. Each of these Gadgets serve a different purpose (a gauntlet on each arm, and a set of armor).

1. Am I correct that, on creation, I should treat each of these as their own Power? i.e. each Gadget can have its own Powers+Extras+Limits?

2. Each Gadget has multiple functions (e.g. one gauntlet has a 'Blast' and a 'Strike' power) - since these are defined at construction, can I treat swapping between the modes as though I had a version of the Instant extra?

3. Does a Gadget that has an innate DR (based on its construction materials) stack with a Resistance (Damage) power that the gadget has?