Speaking of Dom Kane, we have a constant ally we can influence and that's our beloved Olivia. At least the dev made sure she didn't seem like a "second MC" and as far as I can tell, she quite succeeded. So despite the fact that we can control her, she is perceived as a fairly independent character..(imo) So basically, the only restriction for Olivia to be our loyal ally - is for Kane and Liv to have similar moral principles. About Nadia, yes, it would be interesting to know more about her. She seems to genuinely love Kane.
As for leading a faction..it's not very clear how much independent, assertive and self-confident Kane will need it. At least DKane can reach (if we doesn't screw up) the highest rank in this company - Z5. The same Board (including the late Alexander) is Z4.
These things (factions) should worry Sub Kane more, because he is directly dependent on all these woman and this dependence will not disappear. So it's in his best interest to try to climb higher by finding someone under whose patronage he's willing to live on. Dom Kane has a different agenda - to try to take full power into his own hands by becoming the main man in this Corporation.
And even if Dom Kane shares the burden of supreme power with his lovely "little sis" Olivia, it will still be the rule of a King and a Queen (in my case, a queen obedient to Kane)...But does such a Kane, who has all the power, need to be the leader of a faction that will still obey his (or their and Olivia's) will by default? To me, the answer is obvious.