Hi - I've stayed at hotel coz, right next to scc. It's pretty close to town, about 1.25 miles away.
The cruisers - ok - as long as you are not going into town - you really don't need to worry about the cruisers. It sounds like you are looking for a resort to stay at the entire time, and not go into town for dinner or drinks very much. That being said, you can look at nearly any place from downtown - south. The south end of the island you see very little cruisers at all. It's 'out of town' However - it also means if you want to go to town - it's an expensive cab ride (15.00 would be 'expensive' nothing compared to our US cab fairs, but pricey for cozumel).
You mentioned preferring an onsite dive OP. There are some ok onsite dive ops at most of the hotels. However - most of the offsite dive ops in town will pick you up/drop you off from the dive boat from the hotel pier to any hotel from downtown - father south.
So I suggest you book a hotel that you want, downtown or father south..then book a DO that you want to dive with (on the condition that they can pickup/drop off)
I like Papahogs....
Papa Hogs Scuba Emporium of Cozumel - Mexico
If you are booking 3 days of diving or more (2 tanks/day, they do offer 3 tanks) it is 58.00 per day, when paid in cash. A little more if you pay in credit card. They pickup from pretty much any hotel pier from downtown south... they limit their boats to 6 divers, 1 dive master, 1 captain. They try their best to group boats by skill level. The boats are small and fast. They do not have a head. Larger boats with heads usually pack 12-16 divers, with other operators.
So - I've never stayed at the occidental grand - but it's suppose to be a decent 4 star place...
It's south of town - so you won't see cruisers. (Again, if you are staying at the resort all the time - you won't see them anyway)
You can have other dive ops pick you up there.
I priced it from OKC 6 nights all inclusive in august, on orbitz and it was 622 ppdo with flights included (but no diving). So it's not terribly priced.
I think it meets your requirements. The only thing I would point out - if you plan on going to town for 2 or 3 nights or every night - find something closer to town - you'll spend lots on cab fairs round trip.
Also - before you book - call the dive op you want and double check if they WILL pick you up there. There is one or two hotels in town that won't allow other operators to pickup from their pier (wish I could remember which hotels).
Have fun in paradise.