Well, I lurked around the FAQ and messed around some of my own stuff, but there are some things I prefer to ask first.

- Are Droidekas some kind of a vehicle unit unable to have more than 2 weapons or they are actually different from vehicles and thus able to switch weapons?

- Is there a way for a weapon ordnance to ignore shielding and make deal direct damage?

- Is it possible to "stun" a vehicle in the same way Arc casters do with infantry? (I think it may have something to do with slicing status).

- For custom models to be frameskip/ping friendly, is there any difference between "low polygon count + big polygons" and "high polygon count + small polygons"? in any case, what's better? (unpleasant experience with the Attack on Death Star mod).

I am sure there was one more question but I forgot about it right now, thanks in advance.

There might be a bypass shields line, but outside of that all I can think of is giving the weapon a really high shieldscale so that it takes the shields down instantly.

- Are Droidekas some kind of a vehicle unit unable to have more than 2 weapons or they are actually different from vehicles and thus able to switch weapons?

They are like vehicles in that way

- Is there a way for a weapon ordnance to ignore shielding and make deal direct damage?

No

- Is it possible to "stun" a vehicle in the same way Arc casters do with infantry? (I think it may have something to do with slicing status).

There is a grenade that disables/slices the vehicle (kicking the units out).
Just take a normal grenade ord ODF, then change the ord class label from "grenade" to then add you can change the time to whatever you want.

Ok, it may be a work around for my droidekas, now I remember the other question.

- I checked how to add a personal shield to a unit, so, can I set a Droideka Shield to activate/deactivate when it goes from Ball mode to Attack mode? that way I could have the second weapon slot for any other weapon I am planning to add on.

Too bad there is no direct damage for weapons, but at least I may be able to compensate the shielding with some custom weapons.

The main problem with a "slice" effect for vehicles is that I was trying to implement them for space battles as well, but I think that would be killing the unit since it kicks you out.

You already figure that I am trying to bring Ion Cannons into Battlefront 2, and I am basically trying to make it knock shields off and possibily slow down or disable all vehicle's weapon for a short period of time.

Thanks.

As far as models go, the polygon's size doesn't matter (beyond appearance), but poly-count does. Higher poly-count models take more to render, because they have more vertices. Low-polycount is always best for a game. If a certain aspect of the model needs to use more polygons for detail, that's fine. Otherwise, there's no reason to have a high poly-count.