So i read some build on some other websites and often they would say that you can use rush more than once per round. it says "once per activation", so how is that possible?

Also, what do you think about a hybrid-build: brute strengh(3) -> get down(1) -> keep up(1) -> black sun armor(4) -> dont make me hurt you(4). is it possible to get 13EP in jabba campaign?

Plenty of abilities allow for him to move outside of his activation, eg Gideon. He can use Rush each time provided its only once that activation.

Maybe i got that wrong all the time. So when Gideon is commanding Onar to move after his own activation he is able to use rush again?

Yes, limit once per activation, so Rush can be used once during Gideon's activation as well as during his own, and maybe a third time with Keep Up (if used after another figure's activation - using Keep Up the end of Onar's activation is still within his activation).

You can get 13xp in all of the campaigns, tho 12 is the most common # of xp you will get. In JR interlude, one choice gives extra XP and the other gives credits (if you win). If you choose the former, 13xp is very doable in that campaign.

With Onar, you should always get Don't Make Me Hurt You first. After that, all of his skills are on a relatively equal power level and is mostly just personal preference.

i feel like brute strengh is one of the best 3XP skills in the game almost always giving you a lot of crates/doors/terminals without an interaction so i went for it first.

I like the hybrid build of Onar. I really don't think "don't make me hurt you" is the first choice since there are a lot of low xp good skills.

I recommend get "keep up" before "get down" because it can give you possible two space movement per round ( with rush). I strong recommand only get "get down" after you have brute strength. You can use it to cancel the flash of Royal guard to avoid the stun ability.