In answer to the question of whether we can stretch one of the 3s — sure, we can do anything (almost) !
The comments here are interesting. There has been a lot of thought, including each of the concerns expressed.
My view is that a series of par-3s can be very interesting, especially when there are two others that go toward making up the overall round. For one, it is different — and differences are what separates courses from one another. I am confident (for now anyway) that this "feature" is part of the mix and will help define the club.
One of the interesting aspects is that we do not have to do this — e.g., we can easily 'overcome' it — but the idea seemed powerful once we looked at options. For some reason I like taking this approach better when it is not an outright requirement. For example, in the situation where the land might be so rugged or there may be such an amazing opportunity for a series of three par-3s, we are left with the "well, there was no other choice..." or "maybe the site was not used correctly..." or "gee, this is an obvious use for this unusual series..." — but here we have a canvas that will appear (after construction) to have been a mostly blank canvas (the obstacles we have overcome will not be apparent to the golfer because this is generally farmland that 'looks' blank) and, therefore, it would likely never cross one's mind that the routing was anything but purposeful.