Honestly, check this thread out. Guy is running the same system.
https://www.rollitup.org/general-marijuana-growing/513182-newb-grow-journal.html
Also check out
https://www.rollitup.org/hydroponics-aeroponics/269859-all-cap-ebb-grow-users.html and
https://www.rollitup.org/hydroponics-aeroponics/505421-hellraizers-do-donts-outs-ebb.html
You can post questions in these threads and really knowledgeable people will help you and also give you some very great tips to using those systems. They can be a little sensitive but with some easy tweaks you can avoid all of the future problems. That being said...
1. During veg you can 4 times a day for 15 minutes during the light cycle. SOme guys feed longer some guys feed during the dark cycle as well. Kinda gotta play with it and see what works for you. But you do want the bulk of your feeding to be during lights on. Same applies with flower. Most guys feed 3-4 times for 15 or 30 minutes each during the light cycle. Some guys add a feeding during the dark cycle. You have to experiment and see what works for you.
2. This depends on how many buckets you are using and how big your plants are. After a couple runs you will get it figured out. Late in flower your plants will drink a lot more water than 3 week veg plants will. So, in the beginning you will not need to fill it all the way up. In the end you may have to. Also depends on how often you change your reservoir. Most guys are between every 1-2 weeks. You wanna try and get it so you are not constantly filling up the reservoir and also not wasting water. You'll see with time how much you need as your plants get older.
3. Make sure you rinse out all your clayton really well to remove all the dust and everything. Your reservoir is going to creep (pH change) naturally from the plants and the environment. You will need to test and possibly adjust regularly.
4. Easiest way to change your res is get another pump and some tubing. When the lights are on (don't wanna be in there trying to work during lights off) and in between feedings use the other pump to drain your res. Rinse it out and add fresh water,
5. Expensive way...Chiller Cheap way.....Get a pack of water bottles and stick them in your freezer. Add as needed.
ASeriously, check out those threads cause there are a ton of things you need to look out for and those guys have already done all of the guinea pigging.