Your stud thickness grew 1.75" since your original description, from 2x6 (5.5") to 2x8 (7.25")?

The whole-wall R of a 2x8 framed wall at a 25% framing fraction would still only be about R17 with open cell foam, R18-18.5 with closed cell (since you can't get a full 7.25 fill with closed cell, but you can with open cell.) That's still a bit under the ~R22 of a typical ICF with 2.5" of EPS on both sides of the concrete.

For this to even remotely work the window losses of the upper floor (area as yet unspecified) has to be low, and the whole-wall-R has to be higher than that of the first floor, which it isn't.

Rather than 2x8s, going with 2x6 with open cell fill and 2" of exterior iso for about the same wall thickness would deliver ~ R25 whole-wall, at least put the upper story wall area losses at slightly better parity with that of the ICF portion. If the U-factor x area of the upper floor windows is 1/4 that of the lower floor's window & door U-factor x area and you have an R50+ roof there's some chance it might work, as long as the window area of the upper floor well distributed, with no one room having dramatically more (or less) than the next.

The 99% outside design temps in your area are around +20F, not super cold, but cool enough that you'll see substantial room to room delta-Ts if you don't beef up the upstairs wall-R and minimize window area, and go for the lowest-affordable U-factor on the upstairs windows (
On a project I recently advised on had a 99% design temp +5F (only 15F cooler than yours), the whole-wall R was bumped to R40, and the rooms with no direct heating had only 10 square feet of
The window loss out of a 65F room with 10' of U0.20 glass is only 120 BTU/hr at an outdoor design temp of +5F. Keeping the common space at 70F and cross-flowing the HRV was enough to keep the bedrooms above 65F any time the room is occupied, even with the door closed. A typical bedroom's exterior wall area was on the order of ~150' of R40 wall, which loses only 225 BTU / hr at a 60F delta (65F inside, 5F out) so all told the ventilation cross flow and wall-conducted heat from adjacent 70F heated space only needed to deliver ~100 BTU/hr to keep it above 65F, even at design condition. But that approach would have failed failure with ~R18 walls and 20' of U0.30 windows, even with only the ~45F delta-T you'd see at your 99% design condition.

Do the math to get to the bottom line. Your upper floor is almost certainly too lossy to pull this off unless you get serious about high-R/low-U design. A real heat load analysis on each room and a few appropriately sized low-temp panel radiators are probably cheaper than going all out on triple-pane windows with carefully limited sizing, and bumping up to R30+ whole wall (2x4 studs with 3.5" of exterior iso would fit in the same space as a 2x8 studwall.) That's about what it would take to get there without heating the upstairs more directly.

Any time you run your HRV, the energy not recovered by the unit is going to be "lost" anyway. You have to run it a certain amount in any case. All that is happening is that you are using the movement created to help move air from a heated area to a non-heated area.

I have what appears to be a similar situation right now in NW Washington. I am only heating the basement and main floor to 68F with two mini-split heads which represent less than 1/5 of my heating capacity. It is too warm on the second floor without any heat input there at all. A little motion would do well in spreading things out.

the amount you need to run an HRV.. about 50-70 CFM for most homes, continuous... is not enough to move any significant amount of heat to more than one or two areas. if you move air from a 70 degree room into a chillier outlier, you are only moving about 80 BTUs/hr, at most, per degree difference from main room to outlier room. and that's if the full airflow were directed at one room. Not a lot of math required to see that won't help you unless the temperature difference is very high (cold outlier room, hot central).

if you run higher CFMs, you can do more, but then you're wasting fan energy and thermal energy in the exchange.

Even splitting 80 BTU/degree-hour between 3 low-loss bedrooms and the bathrooms, the low-loss bedrooms in the Worcester MA project it still hold the line at 65F for occupied bedrooms and 70F common area (and if the unoccupied rooms give up a couple more degrees and drops below 65F no occupants == no suffering.) With two occupants it doesn't give up any ground at all.

The thermal mass in the rooms also makes a difference in how long it takes to drop, and if it stays colder than the 99% condition for extended periods (rare, but it happens), just opening the doors for more convective exchange is effective. But with loss numbers 2,3, 4x that it fails completely- very low loss numbers are critical to making it work. Just the wall-R of modest sized rooms in uw91's upstairs stackup is going to blow the BTU-budget at 20F outdoor temps, let alone the window and roof losses.

If sufficiently open there will be some stratification and convection it can work on a lower-R house, but sincerely I doubt it's going to be anywhere near enough. The convection & stratification approach sort of works at my uncle's place (on Whidbey Island, WA), with a full 2-story great-room that all second floor rooms open onto, but that's aided by the air currents of the mini-split. It's not perfect at the extremes by any means, but not so imperfect that he's willing to burn propane to make up the difference (he LOVES his mini-split! )