Your readings and settings look pretty good. This is the definition of the pressure you see on the Sleep Report:
Pressure - Average pressure during the selected period (95th percentile for each day; average of
the 95th percentile values for periods >1 day).
In other words for the night 95% of the time the treatment pressure was less than that number. In your case 9.7 cm. So, it may have reached the maximum pressure of 10 that you set. All this is far easier to see on SleepyHead, as you will see the actual pressure throughout the whole night. It gives you a much better idea of what the machine is trying to do. Just a comment, but I am surprised that it is reaching 10 cm. I would have expected your pressure to stay lower than that. On the plus side, the fact it is going that high suggests the APAP is of value to you.
On the ramp start pressure what I do is breathe in quite deeply and quickly. What I am looking for is a pressure where the in-flow feels free and unrestricted like I am not wearing a mask at all. Most people breathe more heavily and deeply when they first go to bed. Under those circumstances you do not want to feel like you are suffocating. If 5.6 works for you, that is fine. You may find as you get more used to the machine you will like more.
ResMed does not disclose how they determine when you are asleep. However I suspect they base it on a very uniform breathing pattern that is not deep and irregular like it is when you first go to bed.
Pressure settings - For now I would leave Maximum at 10. Your AHI is very good. The 95% pressure of 9.7 kind of suggests the maximum should be higher, not lower. But your good AHI suggests it is high enough. You only have a few hours of data, so too early to make a change. As far as the minimum pressure goes, it potentially could be higher, but since you are just starting out and your AHI is good, I would leave it where it is. If your AHI was high it can often be reduced by increasing the minimum pressure. What it does is get pressure up sooner so events are avoided instead of responded to. In other words the machine gets out ahead of the potential problem.
When dumping your water and refilling it, I would just shake the reservoir up to dissolve any sediment, dump it, and refill with distilled. I have to admit that I don't dump the water every night, just about once a week. On the weekly clean I rinse it out with pure vinegar, then tap water with Dawn dish soap, and finally just a rinse with tap water. I do the same with the heated hose, and mask. Best to do it in the morning and then hang them up to dry during the day. I don't bother drying the reservoir though.
Opening your mouth and letting air escape can be a problem with a nasal mask. The usual sign of it is a dry mouth in the morning and a high leakage rate. Your leakage rate is pretty good, so I wouldn't immediately suspect it is a problem.
Good luck tonight!