My advice:
-Use Silver + Something. It can be Silver an Prophets, Silver and Genesis, Silver and TGT, but Silver is awesome because Angels can't be stopped by a lot of the things that most players use some of (Unholy Writ and Charms are everywhere).
-If you want an effective and easy to use defense, use Magicians with an Assyrian splash or vice versa. But be warned, most everyone else will be using some variation of that as well (well, at least that's the case in MN--can't speak nationally I guess).
-Keep your deck at 100-105 cards. In T2-2P, 112-119 can be effective depending on the deck, but in MP, it is critical that you get Guardian/SoG/NJ early enough to use them, and so you want a deck that is as small as possible. My ideal T2-MP deck has 100 cards with 2 hoppers.
-Emphasize negating ECs. A lot of people use all the usual suspects that you see in a T1 meta defense in T2 (Uzzah, Sabbath Breaker, The Amalekite's Slave, etc.) and they use 2-4 of each, so Heroes that negate EC's like Danny, Isaiah w/ Call, or standard FBTN Heroes are very popular.
-Drawing. Probably a no-brainer, but unless your deck has a very effective method of searching that can get around Nazareth, you're going to need some drawing. The number of draw cards you use depends on the deck, but I would suggest several draw cards usable on both offense and defense.
The rest of it is up to your playstyle, the cards you have available, and what your local meta is like. Also, there are very few decks that can compete well in both MP and 2P, so unless you're lazy, I would definitely suggest making some changes to your T2-2P deck. Focus on the LSs you use (some are much better in MP than 2P and vice versa), character/enhancement ratios (should be higher in MP usually, since often you'll be able to get free LSs just by attacking the right opponent, unless you have no heroes), and number of neutral cards (should usually be lower, except in some cases, in order to have room for more characters). Also, know that T2MP is a different animal every tournament, and the same/similar deck that could win a National tournament might not place at some locals or States.