The real question is whether or not he LIKES these people who are giving him the invites. (Outside of the whacko dub dogma that is.) If so, he's fighting a battle on two fronts: Trying to be in for his family that he loves, and trying to be out, in spite of friends that he also cares for.
I think many (most?) of us left the organization from the position of being unpopular or excluded. There are a few here who were perhaps wildly popular, and if they went back would be welcomed with open arms. For them, the rules are different, and it appears likely that Gumby is one of those people.
No matter what he does, he will always be "on the radar" because he is not just "well-liked" but one of those brothers who are extremely popular, makes-every-get-together-better guys. The ones who make other people smile just from being in the room are not forgotten. Ever. C'mon, think about it.
He came on this site, after 5 years of being a prominent EX-jw, and out of the blue, (for some of us,) announced that he was going back to do the fade. He has been met with almost unconditional support for his choice. This is because we truly love him, isn't it? Can you imagine if a well-known but less popular poster suddenly announced they were returning to the WT? That person would receive a very mixed bag of responses. In fact, I've seen it happen that way... some saying "we support what you need to do" and others saying "what the hell is wrong with you? stupid fool." But look back through these threads about Gumby's return... By and large, all compassionate, caring, teasing, but SUPPORTIVE comments.
Can you expect that it will be any different in the congregation where you are known and loved face-to-face? No matter what excuses you makes you will be invitee numero uno for a long time. No matter if you attend one meeting a month, no matter if you never give another talk, no matter if you never knock on a single door. People love you and want you there, in spite of not meeting the numbers. Your only shield from that was being df'd, and I suspect that Gumby had plenty of people circumvent the rules to chat briefly with you, or smile at you, while you were df'd.
I remember people like this when I was a JW. So universally liked that it didn't matter if they were absent at every meeting but memorial. They were still invited to every gathering... year in and year out. Even if they turn down most of the invitations, you can be sure that when the next one comes around, you'll be invited. They'll give the invite to Mrs. Gumby, and put the pressure on her. It's how it works. Low risk to the inviter... you're not there personally to tell them no. It will be hardest on Mrs. gumby. (In fact, she may find it more difficult to have you around as a "fader" than it was when you were df'd.)
Personally, I don't believe you will be able to "fade" in the truest sense of the word. By going back for family, you will have to accept that the whole congregation comes with the family. Unless you completely change your personality, you are "in for a penny, in for a pound" like Gill said. That being said, I also suspect it will be easier for you to stuff your hatred for the Organization and just go through the motions, than it was for you to deal with the loss of kids/grandkids. It's truly a case of choosing the lesser of the two evils.
I don't have any advice regarding getting out of going to the meetings. You just don't go. Your wife will have to endure the questions "where is gumby, we love him and miss him!" at every single meetingthat you miss. That is the price SHE pays for your return. You will have to tough out getting invited to every social gathering from here to armageddon. That is the price you pay... being social and sucking it up when they preach at you or "encourage" you. I don't really see any good way to get out of it.
As far as the other "Theocratic" activities, you need to embrace a tangent that runs just enough parallel and away from WT doctrine so that the elders don't want you on the stage or out in service, but won't tell you so. Instead they'll breathe a sigh of relief when you opt out. I don't know what that would be. Maybe you could get together with Ona and develop a doctrinal "thing" that is not apostate, but not acceptable.
If you really do like these people for themselves, I don't see a way out of socializing with them. You're going to have to suck it up and lose the gag reflex for all things WT. There is no way to "just" get reinstated for family when you're popular. I truly believe that it only has a chance of working if a person is single, or at least doesn't have another JW in the family. You've walked back into the hornet's nest. Now you have to be one of the hornets.