I wouldn't bother with yaktrax or spikies. It will most likely be slushy snow and not that much of it. More of an annoyance than anything. Mostly you want to make sure you don't loose the trail. Keep your group hiking together so that nobody gets lost.
The TR chick-on linked to is a good one and has some photos. The one of the guys crossing Delaney is exactly how I remember it, knee deep but not wide and more importantly the water isn't moving very fast. Contrast that to the picture of Register Creek, now that one is moving fast, I would turn back at that point. But Register quite a few miles down the trail, I don't think you'll be heading that far on a weekend trip.
Make sure your friends know that there are going to be creek crossings and that they are going to get their feet wet. They should have shoes they can wear in the water, either water crossing shoes they brought or just crossing in their trail boots / shoes and being OK about walking the rest of the day in wet boots / shoes. Again, to be safe it is important to keep the group together.
Don't worry about timing the water levels. When you continue beyond Glen Aulin the creek crossings are all bridged until you get to Register, and you probably won't go that far. The trails themselves are flooded in a section below Glen Aulin, not too hard to navigate, but your feet will get wet.
There are bears at Glen Aulin so use bear canisters, they can be rented at the wilderness center where you pick up your permit.
Enjoy your trip and come back here after and tells us all about it.