Ultra Containers (and often coinboxes as well) are generally tied to the specific event the container was released for, as of late usually featuring a special item as the main "theme" of the celebration (such as Healing Emitters or Blunderbuss). Once the celebration is over, the UC is renamed but the rewards stay the same.
So to answer your first question: most likely not, as each event generally has its own unique UC (they are stored as separate items in the game).
As for your second question, the devs haven't disclosed exactly how the mechanics work behind the scenes.
 
Some interesting trivia:

Nothing extraordinary will happen.
The piece of equipment'll continue to upgrade normally - with the "purchase next modification" button being replaced with the speed-up button while the upgrade is being installed.
Once the MU is over you'll be unable to upgrade the item any further and the option to purchase the next modification will appear.

As far as I can find, the Uranium augment has provided a 50% bonus to min/max damage since it was released.
The parameters that've changed are:
reload (0% -> +10% -> +20% -> +15%) reload after salvo (0 -> -40%) missile count (4 -> 2)

Added a link to Status Effects on the main page of the Wiki.
Page: https://en.tankiwiki.com/Status_Effects

You're right, Smoky's chance of landing a critical hit right after another is a negative number (can't happen). The numbers on the Wiki were correct until we updated all the turrets' pages due to the Mk update, and it seems the minus signs were lost in translation. We've corrected the Wiki page in question - apologies for the confusion & thanks @ThirdOnion for pointing it out.

The Wiki Team (with the help of some of our wonderful EN Helpers) is working on it and we hope to publish a complete list in the near-future.

Yes, Titan's dome will still be deactivated by Hunter's OD even if the Titan has Stun Immunity equipped.

Yes, its easily possible with a combination of:
Heavy capacitors alteration (+25% sniping damage) Double damage supply (+100% damage) Booster drone (+205% damage at full upgrades) Hornet's overdrive (ignores protections and double armor supply)