Are you really able to run marathon pace that often for that long? Wow. I always struggle to run marathon pace in my training. I base it on effort and expect slower times in training. It's not until race day that I can dream of going my actual pace.
I'm actually concerned you're doing it wrong despite your ability to run marathon pace so often. Are you truly keeping it aerobic? Are you safely staying away from a threshold effort when you do these runs? Doing 2x5 miles approaching threshold and getting to quit for the day is nothing like the comfort you need to stay aerobically steady for 26.2 miles on race day. Can you promise me that what you're doing is not actually closer to tempo effort?
You actually sound like you're going to crush this marathon regardless. If you get good weather and a good course, then you have it in the bag. Bad course or bad day are the only factors that could stop you now. I'd like your volume to be higher to guarantee it, but your workouts are great.
I generally think of three weeks out as being the last time you can do a long run. Your 10 miler is four weeks out and is a great tune up, so our only concern is that you find a way to get in good volume while still recovering from your tune up.
What you don't want to have happen is do a 10 miler four weeks out and the find yourself blazing a fast 10 miles at the end of a 20 mile run a week later when you're three weeks out. That's too much hard running. I say do recovery running a few days after the 10 miler, some low repetition intervals or just strides midweek, and then something like an easier 18 miler with the last 6 miles being progressive that weekend. Don't underestimate the fatigue of the 10 miler; do trust your last few months of training.
With your volume of training I recommend not doing a serious taper during your last two weeks, but do take the 3 days prior to the marathon super easy. I'm talking like 20-30 minutes easy, strides, and stretch.