Psst...you can't have 5 endurance in your sb.

I like the premise behind the deck, but I am not sure you need the full set of urza lands. My instinct tells me that since you are primarily using it for an early memnarch, you won't have very many sources of blue to take advantage of it's abilities. I'd trim some urza lands in favor of blue sources.

That being said, I do see how all that colorless mana could be used with urza, especially if you have 1 or both of your training grounds active. I'm kinda torn to be honest. Part of me says less urza lands, another part says to drop the green instead. Either way, the lands don't really support the spells very well to me. So here's what I'll suggest to bridge the gap between the 2 ideas.

Chromatic Orrery

This will allow for you to use the colorless mana as u mana for memnarch and even pay for an urza activation all by itself. I'd try it as a 2 or 3 of in place a memnarch and thoughtcast(s).

This is just what I would start with and see if it helps. Good luck and hope your deck performs well for you.

One thing to keep in mind is that online events often lack certain decks that are hard to perform. And by that I am referring to decks that require a lot of repetitive actions and the like. You would see these decks in paper more since the loops can be shortcut to save time. It usually doesn't make a big difference in the meta, but something to note regardless.

Not trying to be controversial, but bounce probably wouldn't need to be a hub. The main role of bounce is to buy time for something else usually and that would probably fall under a tempo type of strategy.

I am not sure if your post is geared more towards written content or not, but "the game theorists" youtube channel did an episode recently on this topic.