3. No.
4. No.
The Channel Number is the Channel Number. It can't just be changed arbitrarily. It is the way the broadcaster identifies their channel. Now if you are talking about a sequence number for sorting channels, that is an entirely different thing. You can re-sequence the channels under "Options > Television > Channels > Manage Channels" using the "Move Up" and "Move Down" buttons. No sequence number required. Save the sequence using the "Save channel order" button so that it will be used in the future. Then if you click on the "Channel" heading in "Manage Channels", MC will toggle through the available sort sequences, "123 ABC" (alphanumeric), "ABC" (Alphabetic), and "Custom", which is your saved sort sequence.
2. I actually thought there used to be a setting to include the Channel Number as a prefix or not in MC, but I can't find that now. I thought my EPG source, "EPG Collector", may have been doing it, but I just checked and it isn't; the XMLTV file doesn't have the channel number prefixed. Or maybe it is part of the scanning/TV setup process. I haven't run that in an age. Hmmm, I can't remember. But the prefixing is happening in MC.
I think I must have added the prefixes into MC manually. If MC has done it automatically, you can remove the Channel Number prefix "Options > Television > Channels > Manage Channels > Edit > Name". MC will remember that and not add them back, unless maybe you redo TV setup at some stage.
If you have logos for all your channels (you do have logo images for all your channels, right?), then you can check "Options > Television > Guide > Hide channel names in Theatre View guide when channel logos are available" and you won't see the channel number prefix anyway.
Thinking further, what EPG data source are you using ABA?
PS:
5. MC has had that for years for ATSC broadcasts. I can't remember if DVB-T OTA EPG scanning was finished or not, as I haven't used it. But it was being worked on.
PPS:
DVB Logic call it an EIT (Event Information Table) scanner because it scans the EIT data broadcast OTA. In the past Australia also broadcast MHEG5 data, like the UK still does. MHEG5 data is much better than EIT data, which is usually pretty basic. That is why lots of people seek better sources of EPG data. DVB Logic isn't particularly special in this capability.