Hi, how are you? I will try to give you some info on your planned dive trip. First of all, Apo Reef is accessible only by liveaboard. You can stay there, but there is really not much to do. Liveaboards come from PG and Coron. The diving in Dauin is awesome, but you say that you prefer 'bigger fish and reef diving', of which Dauin has none. It's black sand diving. Saying that it is the jumping point to Apo Island, which has both. The only thing is that Dauin is incredibly quiet. You can stay in Dumaguete, but I don't like it there personally as it's very dirty.
Coron is awesome for the WW2 wrecks and there are some nice reefs around also. For me, I would(did) choose Bohol. The diving is excellent. There are loads of dive sites and an abundance of dive shops to choose from. I did my divemaster course in Panglao with this
scuba diving center. Panglao is also the jumping point for the great Balicasag Island and
Pamilacan Island diving. There are also many restaurants, bars, and accommodation options for the times that you are not diving.
I guess the main thing if you are going to go on and do your DM course is that you choose the correct dive shop and instructor. You will spend most of your time with them and it's very important that the training is good.
Hopefully, this information helps and you end up having a great time during your training.
Happy bubbles...................