Big yes to Question 3.
As for question 1 it does unfortunately require an online connection at all times but want to remind that there are a few games here, similar situation, that have trainers such Outriders, Rainbow Six Extraction, Plants vs Zombies Garden Warfare 2 to name a few examples. Real complications will be getting around the anti-cheat and how much of the game is server sided which sadly is the case with free-to-play games.
imagine spending 8 hours "getting around the anti cheat" only to discover "playing with bots" still uses server..
best,
Cal