Super cool! Will be drafting this with friends if I win :)

As a huge fan of vintage cube: I love vintage cube!!! As a water safety expert, do not throw people into the deep end please.

Thankful to have had so many opportunities this year to cube with friends ♥️

Doesn't Miracle (static) make you reveal the miracle card before you draw the second card? After rereading the rules, it looks like you must reveal it first (so as not to muddle your first and second drawn cards). Triggers otherwise work as you say, including the option to reveal and not cast

Cards are always drawn one at a time [CR121.2]
If you draw the extra card before revealing the miracle card, you will have missed your chance to cast it for its miracle cost. No, you cannot see the extra card before casting Temporal Mastery.

Adrianna will draw 0 cards.
The last known information for the one ring, before it was exiled, was that it had zero burden counters on it.

It does cost {1} less to cast! On the stack, it only has the characteristics of the part of the card that's being cast. It is an instant, it is being cast, so it costs {1} less.

P.S.
Mana abilities don't use the stack, but if they tried activating Mana Confluence before starting the process of casting angel's grace, they'd lose as state based actions are checked whenever a player would receive priority. Semantics, but hey isn't that what this is all about?

Ashlynn can tap mana confluence for {W}, and they can even use it to cast Angel's Grace (provided they start casting, and then tap Mana confluence once they're prompted to pay for the spell). They can't avoid losing, however, as that will happen as a state based action before anything resolves.

Orcish bowmasters will see the cards drawn and trigger. The triggered abilities will be waiting for state based actions to be checked, so that they can be put on the stack. Then, the turn ends, and those abilities cease to exist before they're put onto the stack.

Yes. Players are still seperate in two-headed giant. Effects that mention "each opponent" rather than targeting are stronger in this variant for just that reason!

Normally I like using CR, but there's a cut and dry ruling for this on Gatherer. No room for interpretation here!

Rest in Peace will exile itself as part of the resolution of Wane, replacing the event that would destroy rest in peace. After Wane is finished resolving, it goes to the graveyard, because Rest In Peace isn't there anymore to replace it going to the graveyard.

[CR611.2C] Tells us that it will not, because the set of affected objects are determined when the ability resolves!

[CR707.2] Tells us that counters aren't copiable, which is the main thing that makes this combo work.
[704.3] is the rule I'll reference to say that State-based actions are checked and performed before triggers go on the stack (Marit Lage creation trigger)
[704.5j] Legend Rule

First, you gotta lose something to the legend rule. I'd recommend keeping the Thespian's Stage. Assuming you do, you get the trigger to sacrifice it and create marit lage. End result is that you control neither of the lands (they're both in your graveyard) but you do control the 20/20 Marit Lage.

Vintage Cube leagues!

Feel free to DM me! I'm also trying to figure out cube content stuff, lol

Vintage Cube and bacon 🥓