Yes, I can relate to all of the things you mentioned.
I must say that from reading other people's post about this topic and looking back on my own experience, I'm of the opinion that there is more drama and fear on the part of the "fading" JW than is often necessary.
For me, there was a huge sense of relief that occurred once I made up my mind to leave once and for all. I discovered that so long as I skirted my way around the initial questions and reactions from JW friends and family,most of them couldn't care less so long as you didn't make them personally face anything or feel uncomfortable. I found that most JW's don't really care about proof or facts or whether or what they believe is actually true so long as they get to anesthetize themselves from facing reality.
The bigger deal you make of it, the more they will feel required to play the part of the loyal JW. If you seem nonplussed when they show concern about you gradually turning down meeting assignments or slowing down in attendance, they'll eventually get used to the idea.
The more excuses, apologies and explanations you offer, the more they'll push.
(After a period of time where you've been canceling out on assignments)
You: Brother Elder, in terms of parts on the meeting, you'll need to do without me for a while.
Elder: What's going on ....is there something wrong.
You: No, not at all...this is voluntary work and I'm taking a break from it for now.
Elder: Well we need you to help out, I've already got you down for several assignments.
You: Well It's never going to be convenient is it? But as I said, I'm a volunteer and I'm discontinuing my duties in that capacity for now.
Elder: There must be a reason for all of this.
You: Once again, I'm fine...I'm simply discontinuing my volunteer duties for a time.
Elder: I'm Going to have to talk to the other Elders and we may have to make some kind of announcement.
You: If you want to be that formal about it, that's entirely up to you, anyway, I just wanted to let you know so you can go about finding a replacement.
No excuses, no apologies, or explanations just a clear and direct message made with full eye contact, that you will not be doing parts in the meeting. You'll have to get used to not jumping in with an excuse or explanation during the awkward silences between questions. No looking down at the floor or body language the gives them the signal to treat you as if you're doing something wrong.
Make it clear to them that this is how it is, no if's and's or buts....they'll have to get used to it. They may be a little concerned about you but mostly they're concerned about how this impacts them and about how to get you to go back to doing what they want you to do.