OK, here's what I have found out, and thank you Steveo, for your information.
1) To set "don't charge during these hours", you can use the Kia Access App on your phone under the Convenience tab. Go to Remote Charge Schedule, then disable your two departure times (unless you can figure out why you'd need them), and go to the next page pressing the > character. Again, I don't care about the departure times, so go to the bottom of the page and press "Next: Review Off-Peak Times".
This is what you really want. I have a PG&E rate plan which is expensive from 3pm to midnight, so I only charge from midnight to 3:00pm the next day. That's 15 hours of relatively cheap electricity. So, Monday through Sunday, I charge from 00:00 to 15:00, and I choose the option to only charge off-peak.
2) I don't have the Prestige trim, but it's ridiculous to not add a feature that is simply software and has no incremental cost. Really Kia?
3) I agree with your description of the drive modes.
4) The Hybrid Drive Mode is described pretty poorly in Kia documentation, but I think you have three choices:
Hybrid or HEV, which holds the current battery charge level and discharges and charges the HV battery as needed.
Electric, which pretty much tries to run the HV battery down since it avoids use of the IC engine.
Auto, which uses the battery judiciously when it can contribute the most "good" (efficiency.)
For my first tank of gas, I achieved 55.5MPG, and a range of 546 miles. That makes me feel much better about owning a larger, less efficient vehicle than a Niro (for example.) It's still pretty damned efficient.
Chuck