As a first step, let's see if lowering the threshold to 80% is enough for them to consider BIP91. Without clear explanation of all their motivation it's hard to know exactly what they'll agree to. Offering 80% is to see if it's the prohibitively high 95% that is one of the major stumbling blocks to segwit. The fact they've included segwit at 80% in their own proposal makes it a clear match for that part of their conditions. However I'm inclined to believe they only care about their 2MB base size hard fork and are agreeing to segwit only to barter that in and won't agree to just changing the activation percentage. Additionally different pools have different motivations and flexibility - btcc and f2pool have already said yes to 80% but then they were already signalling segwit...
Alas my own pools amount to less than 0.1% of the network hashrate so what I have to say makes no difference to anyone or anything, though there are hundreds of PH now running my pool software...
I would not sell yourself short. 0.1% is still 1/1000 of the network. Also you have both the history and technical background that makes you very relevant to this discussion.
From what I have read about thus dispute I agree with your bolded analysis above. That offer will almost certainly be rejected but it is still progress.
Honestly I am somewhat optimistic that some general consensus will come from this. It really is in everyone's best interest to reach a compromise. If you love big blocks then 2Mb is insufficient but still a step in the right direction. If you hate big blocks then SegWit a a step in the right direction and 2Mb represent a finite threat with limited fallout.
We don't need to make a final determination between on-chain and off-chain scaling at this time. Kicking the can down the road by allowing both to be tried in parallel under the vetting and safety provided by the Bitcoin Core team sounds pretty good to me.
Plus though it is not the primary concern here it is worth mentioning that a successful consensus solution to this problem would likely be very good to everyone's pocketbook.