Hi,
To offer the second mouse simply proceed as you did the first: let him strike and coil after he has completely finished the first. No need to force anything.
Yes you can refreeze it. I usually only do this once or twice, depending on the degradation to the mouse. If it got really gross, I'll toss it. The Barkers point out they have fed mice that have been thawed refrozen many times with no ill effects.
My advice would be to keep feeding the large mice for a while. An intensive feeding schedule is 20-25% of the animals body weight every seven days. I know many keepers who use a much more conservative schedule of 10% every 7 days or less.
If you want, you can move up to the jumbo's and save the larges for when your snake is huge and needs an extra in between snack.
Hope that helps,
JonV