Can lords join your rebellion against your faction immediately?

My plan is pretty much to keep working with the Nords, currently as a mercenary, soon as a vassal, and eventually rebel and take them over. I've been working on relation with all the "good" lords and gaining honor for that same purpose too. When the time comes to rebel, can lords I have high relation with within the Nords join me immediately? Do I convince them before taking the fief and rebelling? Does marrying one of their daughter's change anything for this?

I also plan to fight only with Nord troops - will the morale penalty for fighting other Nords be bearable after rebelling? Anything else I should consider? I already have 48 RTR, and have also been working on village relations for recruiting, and enterprises for income.