I'll second Cabana Bay. It's a very short walk to Volcano Bay water park, assuming your budget has room for tickets.
I don't think OP even needs tickets! We stayed at Cabana Bay, and were excited for the short walk to Volcano Bay. But we only ended up spending an afternoon at VB before we gave up on the Tapu Tapu system of line reservation, which is supposed to be a virtual line, but still had us waiting 20 minutes or more when we returned for our slides. Plus, there's no standby line, so if your slide return time is in an hour, you are limited to regular swimming or the lazy river (or not so lazy river, which was fun but so fast moving that we got separated).
Although we had Universal tickets that included VB for four days, we never went back because the CB pools were so great. One courtyard has the lazy river, and another has the water slide. And - this is key for me - there are very attentive lifeguards EVERYWHERE. It's so nice for me to be able to relax a bit, knowing that I don't have to have my eyes on all children at all times. Not to say I'd ever just ignore my kids in the water, but if there are more kids than adults in your party, there's peace of mind knowing that there is someone else looking out for them.
Also remember that unlike Disney, Universal officially allows pool hopping, so if your kids get tired of CB, you can go to one of the other pools and hang out there. Want a more tropical vibe? Sapphire Fall is literally across the street! Get tired of Sapphire Falls and want to party at the Hard Rock pool? Just hop a boat from the dock!
I think the only down side to this is if being so close to the Universal theme parks would be a tease for your kids. I know many families would be okay with this, but other kids might start ramping up the requests to go to Universal, too!