There are different scenarios there, unknown variables.

I look over the guys in my family. I make one of the most competent and loyal soldier my personal driver and bodyguard. A couple or few other soldiers will report directly to me if they are in important rackets, earners, or just a really loyal member who is not afraid to voice their opinions but still follows orders when the ruling is given. Consigliere is by vote by Every member in the family. Underboss, depends on scenario, no one fighting in the family, make the best candidate. If there is tension in the family, and a faction does not like that I am boss, but its leader lives by the rules, has some power or a force to reckoned with and earner, offer him the position as well as negotiations. All works out, approve who he wants to take over his old crew, and allow him to propose someone for membership, this is one time where two members will not be needed. If he does not see any compromise or is just too greedy and power hungry then kill him. I make either a competent family member or loyal member of my crew capo. The capos voted me boss so not really much to fear there. If a capo wants to retire or step down, I allow it and make his suggestion of his replacement as capo of that crew. When that is worked out, I concentrate on legitimate business, real estate, ect. I would meet with my capos at least once a week or every two weeks and change up the routine if need be. Make sure and try to be available for my capos. I will also make sure to have connections politically.
Rackets. Booking and Gambling has always been bread and butter, so no sense in changing that. Loan sharking, real estate, unions, waste management, Auto mobile industry,parking garages and lots, adult entertainment. Whatever it takes to make a buck. Hardcore drugs no way, that shit ruins many lives and families.
Rules: No inductions unless got the ok, and at least two official administration members are present, acting does not count. The guy being brought in has to be at least 30 years old even if it is one of my kids, knows the ins and outs, be known to the family for at least 10 years, be proposed by two active members of the family. If a member needs cash and under a 1000 dollars, no points be charged to him, but the money being loan needs to be known to the crew capo and reported to an administration member, the capo is responsible to make sure the soldier pays back the loan to the other soldier, the capo is in charge of punishment if a loan is welched on and inform an administration member. Every weekend, spend time with your family unless called upon. Killings are only as a last resort.
1) I went over this.
2) Why and I like to see the evidence and reasoning for them trying to remove the other boss. As long as the boss is following the guidelines and not breaking them, then it is his family to do as he wish. If he is breaking the rules and guidelines, then he should be disposed of. I'll make enemies with my actions if the bosses hate the boss of that family, but I am backing up as I see no reason why he should be disposed of. If the two bosses concocted a story to get the other boss in trouble, then make it known throughout the society and allow them to step down and retire, if refuse, there is always someone wanting the top spot in their families.
3) I am in prison for 10 years? Or 10 years is the sentence? If 10 years is the sentence I can be out in 5 years, there are many things to get good time off. Before being locked up, I would make sure most business is taken care of, inducting members and killings and keep the title of boss. No killing or inducting new members unless this was discussed before and the timing was bad but still gave the ok. Underboss is now the acting boss, unless he too is with me in which case no new members will be permitted and the Consigliere is the new acting boss. If I am in the can for 10 years, I relinquish my title, and let the capos vote for new boss, I dont see appointing the underboss as boss, just acting boss. If the capos believe the underboss is the right man for the job, then they will vote him as boss. Just leave it up to the capos. Consigliere still stays the same for everyone to vote for that position instead of just the capos.