It isn't clear to me whether, or until when, first-stage investors can pull out for a full refund. Has this been clarified by the dev (for any case other than the project completely failing to launch)?
If you are with escrow you can pull out even just one day before the launch
It's still your money if it is in the hands of an escrow

Can dev and/or Anon136 confirm whether use of escrow gives me some get-out option, even if dev delivers 100% on his promise?
It does. You may opt out for any reason you wish or even with out any reason at all. However i will not speak to the morality of backing out even if he delivers on all of his promises, that's for you to decide.
did terms of escrow as described by OP allow for pulling out? I would think that unless specific terms were in there allowing bailing out, that a REAL escrow service would hold the funds until "eXo was sent", then would disburse the BTC to OP. This is the definition of escrow.
And when I use the term "eXo was sent" I would expect eXo to be sent directly to purchaser, not through escrow service, since escrow service can check blockchain to see that eXo was sent. Also by the term "eXo was received" the eXo I refer to BETTER had some advanced features available to make sure we can tell the eXo product isnt just some closed source clone of existing coin.
ok so i still need as clear of an answer as possible on this point.
So I will not interpret anything and only release funds if that is what my customers wish. Do you agree to these terms?
my understanding from what you wrote is that these terms are agreeable but in my line of work clear cut yes or no's are very important.
alright than just one word as answer: yes