The only portage that sticks out in my mind from that route is the one connecting Maria to Jesse. It's probably not the worst in the park, but it should get an honorable mention. It has some pretty good boot sucking spots.

As far as fishing goes, I'll give you one little hotspot. There is a small island in the middle of the Sturgeon Narrows with an obviously well used camp site on it. The current in the channel on the south side of that island flows east to west if my memory serves me. If you paddle out into that channel to the south of the island, and drift from a couple hundred yards east of the island, to a couple hundred yards west of the island, bouncing leadhead jigs with some kind of 3 or 4 inch twister tails off the bottom, you should be picking off walleyes with ease. I'd say you're probably working water depths of 20 to 30 feet threw there for the best action.

coming from Stanton Bay, or French Lake for that matter, I'd
be more likley to take the B-chain down to Fern (more scenic, but more portages), then over thru Oliphaunt - keep that as an option if you find out that Deux Rivieres is too low (the outfitter will likely have an idea on whether its ok or not - I assume you know that you need an outfitter to use Stanton)

for the return, I like Lonely Creek over Jean Creek, just because its easier to get to if the prevailing westerly winds are doing thier thing.  Its "smaller" water overall.  Jean creek is nice, just that you have to make that run all the way down Sturgeon. Travelling Jean Cr will be different than the maps show - a couple of the portages have been flooded out by beaver dams - at the BIG dam, you can pull your boat to the far left end, and slide it over there, rather than trying to negotiate the  5' high dam.

check the portage data base on here for Oraian creek - you'll find references to it being a mud slog in low water, so if you do get into Quetico Lake to Oraina Lake, you may want to portage up into Jesse rather than going Oriana-Hamburg-Maria - those are the sections of Oraina Cr that can get low - not sure that you were planning it, but Oriana to Hamburg to Maria is a nice route.

I have pretty much always gone at end of May into mid-June, and rarely has the water been "too low" anywhere at that time, though there have been exceptions.  so far this year, I think the water is below average ? but that can change with a lot of rain - but as dry and warm as this year has been everywhere, water levels in the small creeks may come into play.  I'd think though, that Lonely Cr and Jean Cr would still be ok.

last year, there wre some fishing boats stashed on Sturgeon, so likely this year it won't be a motorized lake for LLC guides - there is a really nice sand beach peninsula campsite on the south side of Sturgeon, about mid-lake if you go that way - that was where the boats were last year. would be a great sport for swimming

Deux Rivieres may not be navigable in the traditional sense, regardless of water levels.  Beavers play havoc with it often and it may be a long mud-slog not far south of Twin most of the way to Sturgeon.  Two years ago I took it in a solo canoe and had to walk along the "bank" (and I use that term VERY loosely) while towing my canoe.  My brother and his friend in a tandem struggled even more.  We eventually ended up trading off who towed the tandem to preserve our strength.

If it's calm, there's tons of walleye in the main body of Sturgeon.  Just weave amongst the islands and you'll be stopping often to fight fish.

Lonely has at least one HUGE pike in it...see my avatar for appropriate size details.  Lots of walleye too.

Snow Dog - curious as to what time of year that was, when you had to drag boats down Deux Rivieres ?

Was through the Maria to Jesse portage 2 years ago and it wasn't bad at all. The new corduroy prevented any muddy going. The worse portage by far was Cedar portage between Jesse and Oriana. Coming out of Jesse on far west end was a leech-infested old beaver pond barely deep enough to pole through. That was mid June. I will never go that way again. Oriana was a delight however, moose skeleton near portage going out or Oriana toward Quetico Lake. Good luck and most importantly, enjoy the valuable time with your son. My son has always been my sole traveling partner and the bonds made be these type of trips are priceless!