They won't change their last names officially but Shane and Ilya very much have a "what is mine is yours, what is yours is mine" attitude to it.
They arrive at a restaurant, Ilya leading Shane inside, smoothly telling the maître d': "We he have a reservation for Hollander." "Of course. Would you let me show you to your table, Mr. and Mr. Hollander." And Ilya looks so proud and so happy and Shane squeezes his hand tightly.
Ilya wants them to have new bespoke suits for the NHL awards, he got a rec for that hidden gem of a Québécois tailor, and makes Shane call him. Shane rolls his eyes, they have enough suits yet he indulges his husband. He stares at Ilya across the room when he calls and says. "J'ai besoin un rendez-vous pour deux personnes. Oui. Mon nom est Rozanov." Shane only notices after ending the call, blushing slightly, but Ilya comes sauntering towards him, grinning like the cat that ate the canary. "Oh, Mr. Rozanov it is, I see. Maybe we should swap."
They go on a family vacation together with David and Yuna and Ilya introduces them with "We are the Hollanders" to all the other hotel guests.
Shane introducing them as "We are Shane and Ilya Rozanov." to the new neighbours.
It's exciting and comfortable at the same time these little moments of being so openly married, of being seen a family together, and for this it really doesn't matter which name they use.