And that occurred after the currency crisis had started (the debt swap into Eurobonds was because of the GKOs). I am not sure what the US has to do with it. I am not sure what "Soviet-era debt" has to do with it (that debt was very soft, was rolled over multiple times in the early 90s, and wasn't related to Russia's problems). I am not sure what the IMF has to do with it (the IMF came in after it started...that is why the IMF came in).
Yes, it would have...that is self-evident. The reason the peg collapsed was because the free market/floating rate was lower. The only purpose of the peg is to stop the currency going down (again, this is a weird, self-evident proof...saying that the currency wouldn't have collapsed if they had a floating rate makes no sense, it would have collapsed faster).