Nonono, ignore this "you need a great meeting hall and a statue garden" nonsense.
What you really need to get them to socialize
fast is lack of work for the little buggers so that they hang around at the meeting spot, and a meeting spot. Yes, a meeting
spot. Make a zone of 1x1 tiles somewhere. Declare it as your one and only meeting zone (i-m). All of them and the dogs and cows will now be stacked on that tile and on the 8 adjacent tiles whenever they have nothing else to do. They will chat and socialize and make friends and grudges in no time.
Once they're in lover relationships, give them some more time to sort out their religious issues (which of the two gods they want to worship from now on), and then they will marry.
As a bonus, since you have no meeting hall, there will be no 2 year long marriage party afterwards.
A huge meeting hall plus statue gardens plus a well meeting hall and whatnot will occupy too much space. One lazy dwarf will sit near the well, another will sit in the dining hall, another at the meeting zone, and the last in the statue garden - that won't offer any chance for them to start relationships. Also, your cows will wander through your fortress from then on, from one meeting hall to another, and these animal migrations annoy me to no end.
Sure, they may be impressed by the quality of those tables and statues, but a good chat with a friend outweighs these good thoughts any time.
Sleeping arrangements for married couples? Your dwarves have rooms?
Nah, erm, seriously, they don't need two beds in a private room, and they don't need to sleep in the bed at the same time. Dwarven sex is all done with spores.
Instead of the tiny meeting zone (which is really the best and easiest way to get dwarf relationships going), you can also do some work with burrows. Make a small (2x2 or 3x3 tile) sized burrow, assign everyone who isn't in a lover relationship yet, name it "get it going", and wait.
Meeting zone is really easier and faster for that though.