After a fun and in-depth tire discussion with Johan at PMC, I went with the Toyo Observe GSi-06 in their recommended size of 255/60R18, load index 112.
That's their guaranteed fitment, as the one-inch narrower wheel can cause surprises when teamed with the offset on a 265/60R18. It's also the CX-90 MHEV GS trim's oem 18" size. The theoretical overall diameter is a half-inch under my 19" fitment, but I'll take that over rubbing.
So DTD Blizzard alloys, programmed tpms sensors, mounting and balancing, new chrome lug nuts for the winter kit, the Toyos, mounting and balancing and free shipping is $2,028+tax at my door, ready to bolt on the car.
I will test-fit front and rear when they arrive.
I re-read my comments here on the same Toyos in 245/60R18:
https://www.autohebdo.net/editorial/20220317/honda-ridgeline-touring-2022-essai-hivernal/I remembered I liked them, but not in so much detail!
Next: floor liners...