All that stuff helps. In the grand scheme of things missing 1 leg day wont mean a damn bit of different 10 years from now if you hit 90% of the other ones.
If it means the difference between playing well in the rugby game and being unable to play (I've been THAT sore before), I would just skip the leg workout.
Maybe just work up to a 1rm on squats. It will challenge you and leave you with no DOMS for the most part.
If you must do the leg day, double down on the Surge or a some kind of PWO drink, and consume a ton of BCAA throughout the day (upwards of 30-50).
But like I said, if you get as sore as I get sometimes, I would either take it very easy or just skip it all together. Rugby should be a good leg workout with all the sprinting anyway.