This is the guy I would like to build since my first R2D2 is almost finished.
BB8 appeared in SW EP7 and is the work of Matt Denton and Josh Lee.

Matt Denton & Josh Lee

This is BB8 MK1 (or Red Carpet version) made for "The force awakens" premiere.
Not used in that movie.

Above and right:
This is (propably) MK2. Made for "The last Jedi" and was used in that movie and also "Rise of Skywalker".

Matt and Josh in a 7 second clip from "Galctic Builders" showing the MK2.

The 7 seconds from the TV-show only shows part of the mechanics and only from one side. So my work this far is VERY much guessing.

This is not accurate as far as I know now. It should propably be ordinary caster wheels instead of the Pololu ball casters I used above.

Since the battery arrangement is removed on the 7 seconds of film I simply guess that something similiar as in MK1 have been used in MK2 as well.

Light yellow parts are also guessing, very hard to see on the 7 sec film.