i think the key in this discussion is our definition of independence. many types want to be independent in some way or another. as a 5, i like to be independent to pursue my ideas freely without restriction/restraint on time, finances, the interests of a group, etc.
8s, i feel, want to be independent from the feelings of others, so they try to become the boss, in-charge, etc. they don't know how to work or play the feeling game well, so it is burdensome, exhausting, viewed as an excuse, etc. they think- fuck that noise, they should take care of themselves. why should i have to look out for them, you have to go after what you want, you can't go thru life whining about your feelings and acting so entitled.
there could be another way to be an 8. i'm not familiar enough with the core need to recognize how it could fit into another enneagram type.
an enfj tho, would feel threatened by Ti. i don't think fear of others logic can produce enneagram 8s. control, in this case, would have to be drastically reinterpreted to "by manipulating others, creating alliances, and boosting harmony within the group that hosted your own opinion of the situation." which sounds far more like 3w2 behavior than 8w_. when the 8w9s try to peace-make and create harmony, it's way more laid-back let's all get along fuck it let's get a beer kind of interlude. it is a strategy of more passivity rather than more skilled assertion, a kind of looseness.