I would not expect any modding support until official release in a year or so.
Larian of course is aware of the desire for modding and are making decisions that won't preclude it, however it likely won't be available for a while.
It's going to be a fine balance; if they leave it too late there's a risk that the moment will have passed. As Larian are still trying to establish themselves as a modder-friendly studio I think it would be an oversight to give it too low a priority.
I dare say that it's less important that the modding for various platforms/systems/etc neither need to be kept in sync nor completely compatible let alone identical, though it would be preferable if the stuff they produce is portable between them. IMHO that's more of an ideal than an immutable requirement though. And obviously (I hope) just my personal opinion on the subject.
