In December I was diving with 3P's and they/we were picking up and dropping off a couple of divers who were staying at the Cozumel Hotel & Resort for a week and chose to dive with 3P's. It was really easy for them and they had done it in prior years. However, as you appear to be new to diving, I'd say you'd be just fine keeping it simple with their on-site dive op, Dive Paradise.
I haven't stayed at Cozumel Hotel & Resort but have heard good things about it. From what I've heard, go with the AI option over the breakfast only plan. The AI option only costs a few more bucks more (literally a few more bucks) and that gets you 3 meals per day + drinks. I've heard the AI option upgrade is SO cheap from the breakfast only plan that they could go into town and pay for dinner when they wanted to without thinking they lost $ by doing so and they always had the option to stay put at the resort and dine there whenever they didn't feel like heading out.
Looking at the Dive Paradise website... 7 days of AI accommodations at the resort with 14 dives with Dive Paradise for $1,234 per person? That is some good value for your AI with diving dollar. I beat the 3P's drum here but for your first trip to Coz and being new divers, I say keep it easy and simple and book the dive and stay package through Dive Paradise. Others here may disagree but they have probably been diving the island for decades (I'm going on 18? years now myself) but when visiting a new dive destination it is much easier and less stressful to book it all at once with an AI option if available and forget about it. If you decide to return to coz after this trip then you can start playing around with all the various accommodations and independent dive ops than can service you. Just my thoughts.