Not a straight forward answer to your questions
The furnishings in the Bliss are newer than in the Mayan Palace, and are more modern. However, in 2016, only a portion of the Bliss was open. They were doing construction in the building nearest the reception at the MP. The third building seemed to be not in use.
My preference would be the MP if I was in buildings 1 to 10, and the Bliss over buildings 11 to 20. But you likely won't know which one you are in until you get there. The largest factor in choice is the distance to the pool area. Look at the Vidanta website and you will see the location of the buildings.
In 2016 we were in the Bliss and the MP. Both of the hotel rooms, in our case, had two double beds. But, some of the rooms have a king size bed. Where there is a king size bed, there is a couch that can be made up into a double bed to achieve the two plus two sleeping arrangement. Remember that the hotel room, called the Master Room, does not have any cooking facilities or refrigerator of any kind. You may be able to talk house keeping into providing you a coffee maker, but even that isn't guaranteed. You would likely be better off if you have the one bedroom in either the Bliss or the MP.
I don't know the end cost of the MR through II as I don't belong to II. Through some people that own RTU, Vidanta has a program by which you could reserve a room at $50 above their regular maintenance fee. Through this program you would be able to reserve a larger unit five months before you planned to travel. I'm guessing that a one bedroom MP or Bliss would be in the $800 USD range, but am not certain.
Feel free to PM me if you have more questions.
Cheers.