1. If you go with one of the well reputed divecenters, no problem. You can trust their gear. The level on the dive industry in Egypt is very high (50+ years experience from dive tourism). There are bad ones, of course, but many good ones (in no particular order): Emperor, Sinai Divers, Colona, James & Mac. And more.
2. Since I haven't done day diving in a long time in Hurghada I can't really recommend one above the other, but James & Mac were good back in the day inme. You can hire a DM just for you, don't know the cost but usually Egypt isn't that expensive. A good idea to get the most out of your single day diving.
3. If you pay for a personal DM, you van get away with not having a loogbook. There are all types of dives and depths in the Hurghada area are generally shallower than in e.g. Sinai (not as many wall dives). There are a number of nice wreck dives on Abu Nuhas reef. You will see nice and colorful hard and soft coral and and fish of smaller size. Perhaps a few reef sharks and rays. Dolphins or a manta ray if you're lucky. It depends on season, location and luck. Water is normally clear and blue and fish and coral diversity is much greater than in the Carribean. Anything is possible, nothing is promised.
4. Most centers offer Nitrox.
good luck
