4.1 Availlability of mods and construction set
4.1.1 Will the Construction set be available and on what platforms ?
According to the official site, the Construction Set is available only for the PC version only.

4.1.2 Will the official mods be available and on what platforms ?
Bethesda committed to make official mods available to the XBox 360 through the Marketplace. They will also be available for the PC version as usual, by downloading from the official site.

4.1.3 Will the user made mods be available and on what platforms ?
They will be available for PC users as usual, by downloading from the multiple mod hosting sites. Still no definitive answer for the XBox 360. Bethesda is looking for solutions

4.2 Legalities
4.2.1 Can I sell my mods ?
No

4.2.2 Can I use assets from previous Elder Scrolls Games ?
No (answered to Silgrad team), unless you get a special permission from Bethesda.. Assets includes but are not limited to music, models, textures

4.2.3 Can I use assets from other Games ?
No, unless you obtain permission from the company (good luck!!!). You must have a proof of consent.

4.2.4 Can distribute assets I created ?
Yes.

4.2.5 Will Bethesda become owner of the assets I created ?
No. Bethesda only become owner of the esp/esm according to the license. The ownership of all artistic assets you included with your mods is unchanged. If you created the music, you still own the copyright (for example)

4.3 Technicalities
4.3.1 Are Morrowind models compatible
No

4.3.1 Are Morrowind mods format (esp, esm) compatible
No

4.3.2 Is the flex modifier used
No

4.3.3 can we make the clothing move
Yes, using havoc

4.4 Autonomous regions
That subject is large enough to deserve its own section

4.4.1 What are autonomous regions
An autonomous region is like an exterior region equivalent to a Morrowind map.

4.4.2 What are autonomous regions used for
> Walled cities.
> Every Oblivion plane has its own autonomous region.
> Region not accessible by land (like a far away island)