Will there be other currency than the Premium Currency 'Dynamight Gold'? If so, will it be like most MMO's, with Copper/Silver/Gold coins or just gold, or will it be like PoE, with usable currency?
There will be non-premium currency that will most likely not be exchangeable for dynamight gold. We don't know what form it will take but it will most likely be traditional currency.
Is it possible to trade between planets, or does each planet have their own economy? Will there be an AH, or will the trades be between players (RS style before the GE)?
Trading between planets is one of the core aspects of the economy because each planet planet has it's own unique resources. There's no universal banking system or auction house; players have to physically transport economic resources around.
What will the loot system be like? In the Alpha Video we didn't see anything related to this. Will the items just pop on the ground after killing a monster? (If it does this, how will parties divide loot/how will you combat ninja looting?) Alternatively, will we have an looting UI, and we roll on the loot (like WOW).
Looting will mostly consist of resources and currency. The goal is for every piece of gear to be crafted by players, though they have mentioned identifying enchanted items. I don't know how those two concepts don't conflict, so that will require clarification from DS. (Maybe identifying is how you learn crafting recipes?)
Ninja looting is possible but is considered a hostile action and thus is incapable of being committed by good aligned players against good or neutral players. Neutral (and evil?) players will get flagged as thieves for 24 hours.
What will the items/gear be like? Again, something we disn't see in the gameplay footage. Is this the way to progress in the game? Can we acquire Items in other ways than crafting or buying them? Will the items/gear be almost random (Grim Dawn/PoE style) or will the items/gear be like in WOW?
There's no gear progression. The gear you start with is supposed to be competitive with any other piece of gear anyone else has.
Will there be Instances/Dungeons/Raids? To me, as a PvE junkie, these have been the best part of any MMORPG. Of course, Instances could be solo'd, with scaling difficulty if a party joins. If there will be these Instances/Dungeons, how do we access them? Will we have procedurally generated dungeons, or will they be pre-determined? What will be the merit to do these dungeons, if items are crafted by players, and not dropped in Instances?
There are no private instances. Dungeons will be part of the open world. There will be procedurally generated temporary asteroids, but they seem to serve GvG conflict over resources.
What will endgame look like in Fractured? Other procedurally generated games (read No Man's Sky) have had the problem of getting boring quick, because there is no feeling of progression and only repetitive tasks. What will I be doing after 500+hrs on the game? What is the way to progress after that?
From what we know: Housing/settlement building, GvG politics/conflicts, PvP, maxing out all skills, crafting, and trading. If there's more than that I'd like to know too.