Actually, I was the one who proposed the velcro solution. I have used this solution on 3 pairs of A-E monkstraps--the Saxon (the older one, a rubber-soled, moc-toe, monkshoe), and 2 pairs of Concords. The creaking you hear is the bottom of the monkstrap rubbing against the tongue and facing (opposite the strap side), on the one hand, and the underside of the facing rubbing against the tongue. The solution is as follows: stick a strip of the woolly side (not the hard plastic loops) of velcro along the length of the strap (up to the hole you put the prong in). In addition, cover most of the area on the underside of the facing (which contacts the tongue) with the same woolly-side velcro in maybe two strips. Cut the velcro so that it lies maybe .05" from any edge (and hence doesn't show).
When you put your foot into the shoe and cinch the strap up, the velcro will be completely invisible, and, contrary to what you might expect, the strap won't
look as though it is being pushed up by something underneath. The velcro just completely flattens out, and the shoe looks identical to what it would without the velcro. With my monks, this has completely solved the problem. After a garrulous period at first, I haven't heard a single peep out of them since, not even a weak and timid one.
Before arriving at this solution on my own, I had contacted A-E about the problem. Their suggestion was to sprinkle talcum powder over the surfaces that made contact. This approach did help a little (but didn't completely eliminate the creaking), but was messy, with the powder getting all over the shoes, and, in a fairly short time, it all wore off and had to be applied again. I found it curious that this happened at all with A-E shoes--and that they knew about the problem, but hadn't solved it on their own with their monkshoes. The explanation I got from the A-E people was that it was the leather finish that caused the problem (hence the lubricating benefits of talcum powder, I guess). It's been interesting to me that none of my other monkshoes has exhibited the problem in the first place. This would suggest to me that it is either the leather A-E uses or the particular finish they put on it--and perhaps the inner-lining leather is partly to blame too--that results in this very annoying phenomenon.