Hi Blueberry,
Frenetic Enigma here; as best I can, here is the info for the questions you've posed:
1. Season Mode
2. Current year (2019-2020 Season)
3. No
4. Full control of all 31 teams (I've been playing Season Mode this way for as long as it's been possible in the EA NHL Series)
5. It doesn't matter what players are being traded - all trades are blocked by the "less than 2 playable goalies" message; most recently, I simply tried to trade Ilya Kovalchuk from LA to Montreal
6. I'd made all trades that had occurred in the real NHL in the 2019 part of the season: a quick count would suggest approximately 12 trades
7. Not a custom roster
8. No screenshot at this time, but the screen message that pops up should be very familiar - it has occurred sporadically over the years, but could be circumnavigated until now
9. Yes, tried once (could try again, but not convinced that'll help)
10. No, I do not use an external drive (I am using an Xbox One X 1TB version)
Really hope this helps, as we've recently had two trades (Zucker to the Pens tonight) and the deadline is only a couple of weeks away.
Please feel free to PM me if you require any additional feedback/information.
Thanks,
Frenetic Enigma