I appreciate that OP wants advice/tips and not just discouragement, but this is a bit of both. Because frankly, we've all been there and wish we could kick our naïve pre-kid selves who couldn't even begin to imagine how different our lives would be. We all "needed" the vacation of our dreams too, but didn't get one until the kids were quite a bit older and more self-sufficient (and heck, I'd estimate that our trips are still 95% parenting; 5% vacation).
I know you hear all these stories of the people who had an amazing cruise vacation with babies, and maybe you'll win the baby lottery too, but that really really depends on the kids. Just like some women have blessed pregnancies and others have nightmare pregnancies, there is a whole spectrum of difficulty level with traveling with kids and so many things you can't anticipate until the baby actually arrives (and even then, things can change month to month as the children grow).
Unless
DCL changes its cancellation policies, I also feel like a cruise is the WORST kind of vacation with babies, because you can't cancel or rebook without penalty if things go wrong, and you can get stuck with denied boarding or quarantine if the kiddos get sick (which they often do at that age since their immune systems are still learning). And once you are on the ship, you are locked in and can't easily pack up early or change plans if things don't work out.
I don't believe any of the Europe cruises are typically short 3night/4 night options, which is what I would normally recommend for a first cruise with small kids to test it out. But if that changes in 2022, definitely go with a shorter cruise.
But in terms of actual tips, if you do go on the cruise:
(1) Stock up on disposable one-use bottles/sippy cups (not easy doing dishes in the tiny cruise ship bathroom sink)
(2) I actually did like having a "real" stroller rather than an umbrella on the ship because it's handy to have good under-stroller storage to stash their giant diaper bag and all their other "stuff" (jackets for the cold dining rooms, stuffies etc.)--and we also needed it for ports where we often had to take the stroller places where an umbrella stroller's dinky wheels would have been difficult to manage (e.g., cobblestones, beaches, grassy areas). We got one that folded up small enough to fit under the bed, because there is really nowhere in the room to store it. Would try to get one that is as small as possible while still having all the functionality of a full stroller--that donkey is going to too big IMO.
(3) If an elevator opens and it has room for the stroller but is going up when you want to go down or vice versa, get in and take a detour in the wrong direction--it's often faster than waiting for an elevator going the "right" way.
(4) Bring your own laundry detergent. You'll be amazed how much laundry you'll need to do at that age between the messy eating, crawling on the ground and blowouts, and that way you can choose a detergent that is a bit more gentle for sensitive baby skin than the stuff DCL has in the laundry room vending machines.
(5) Bring lots of all-over body wipes (we used johnson and johnson but there are other brands) these are much larger than standard hand and face wipes, and can be used to wipe down the baby head to toe when they get particularly messy and need freshening up, and they allow you to go a day without a bath which is handy with those tiny cruise bathtubs.
(6) Take turns where one parent goes out during naps in the evenings, leaving the other parent in the room. That way you can both do things you like without having to depend on nursery, which doesn't always work out (at all), but especially often doesn't work when the kiddos are sleepy and cranky and not keen on dozing off with strangers in a strange place.
(7) Bring a pacifier/sucker or a bottle with water for the airplane, even if they have outgrown it at that point--sucking on something helps them regulate ear pressure so they don't have as much pain in their ears during takeoff and landing (this affects small children much more than adults)
(8) Don't overplan or overcommit. This is going to be hard because most people who use these boards are by definition, people who do some planning before they vacation. But the biggest meltdowns (both of the kid and parent variety) happen when you try to make plans (especially non-refundable ones) and one or both of the babies isn't cooperating. You really want to be able to just be flexible and change up plans for the day as you go.
