If you haven't made any games yet, then jumping into a multiplayer isometric game is probably a mistake. You'll quickly get overwhelmed and lose your motivation as you hack things together into an unmaintainable jumble of spaghetti code.
Have a look at this article. It tells you which games you should make first and why:
Oh, and I really liked what little time I spent with the Irrlicht Lidgren networking library. I don't have a ton of networking experience but I got some basic multiplayer logic going without too much headache.
2) I know I just need to commit to something and I want to at least start my programming journey with video games. From what I have read it sounds like I should probably start with C# as my first language. It seems that it will allow me to do more with development than Python may in the realm of video games. I know Python has capabilities but C# has been used extensively in professional development and is also able to be used on Mac OSX if I am understanding things correctly.
Pick something and get started! I recommend C# and Unity, but ask 100 people and you'll get 100 answers. They'll all have good reasons. But if you don't pick a direction and go, a year from now you'll still be standing in the exact same spot deciding "what would be best" and STILL not doing anything. Analysis paralysis at its finest.
One trick to avoid getting distracted is to avoid the temptation in the first place. It's tough when the tool you use to be productive is the same tool you use to goof off. I suggest that you create a Developer persona for your productive YouTube watching. Only watch and subscribe to dev related videos when logged in with your dev account. That way all the history tracking and content matching they do will focus you on dev.
If force yourself to take the time to log out of goof-off mode and log into dev-user, you'll hopefully gain some psychological benefit out of that too. In order to goof off, you'll have to expend some effort log back out of your developer user, then log onto your goof-off user. Then your goofing off is no longer accidental. It's a conscious choice that you're less likely to make.