As always, just look (in the FactionUnit.ini mostly) for similar units to look how it works....
1,2 : look battlemaster for "horde"
3 : I think it is auto when horde is activated
4 : look if the horde bonug give an upgrade (so you can change the weapon ti be more powerful) or just a bonus percentage.... I think it is just a percentage though.
5 : Haven't seen other units doing this, must be impossible
6 : See patriot
7 : See pathfinder
Hope you'll find out.
Good luck