If G0-T0 could effect worlds directly he would not have needed the Exile to his work for him.
Again you under rate Zann and his forces while making G0-T0 out to be some sort of god. Zann does not make many, if any, mistakes and G0-T0 is not as clever as you think, squid face hide his planes from him extremely well, not to mention G0-T0 gets taken out by the remote. Mr Fenn, he has a name you raciest,
is far clever then you give him credit, he would scrap any HKs that come after him, they didn't do too well against force sensitives, not to mention he is close to 4'000 years old, he was alive during the Great Sith War, you don't live that long in the underworld with out great skill. He also EXTREMELY loyal to Tyber so your beleif that he would turn is laughable.
You need to do a little more reading up on G0-T0. His operations on Nar Shaddaa influenced several worlds throughout the Republic, keeping them from going bankrupt. Through his guiding hand the Republic was able to stay strong and not crumble in on itself. So yes, he can influence worlds. He just doesn't do it guns blazing like Zann.
Squid-face gets killed by the Ubese assassins, who turn against him once hired by G0-T0 because he finds out his plans. So no, he did not hide his plans well.
G0-T0 does NOT get taken out by the remote. Again, read more up on G0-T0. In cut content from KOTOR 2, G0-T0 defeats HK-47 if the Exile is darksided. Yeah, defeats HK-47. However, if the Exile is light sided,HK-47 brings along two HK-50s, and all three combined finally manage to kill him. So no, he was not killed by the remote.
You're wrong again. The HK-50s did not do well against the Exile because they wanted her alive. To kill Urai, all they have to do is snipe his head off. HK-47 killed hundreds of force users, and these HKs are upgrades to him.
I never suggested Urai would join G0-T0.... However, if you want another reason why Hanhaar would stay with G0-T0, the beast would probably want to test his skills against Urai. From what I can tell, Hanharr doesn't care about credits, just bloodshed, and he has more opportunity for bloodshed fighting for G0-T0 than Zann.