I will take a guess. Michigan admits about 440 students a year. They admitted 289 in the first round and their yield has usually been around 60%. Assuming that the yield holds up for the first round (I don't know if this is a correct assumption or if yield might be higher or lower for 1st round) then 174 students will matriculate, leaving 266 spots open for the last 2 rounds.
Adcoms said that they expected 10% of applications to come in during R3, but as we know, admit rates are lower for R3, so perhaps 30 spots will be filled in that round, leaving 236 spots to be filled in R2.
Again, assuming a similar yield rate in R2, it seems like approximately 400 students will be admitted in R2, or about 25%. This is lower than the 33% admitted in R1, but as has been speculated, R1 applicants might be more qualified in general. The people that have their stuff together and have been planning for B-school for years will apply in R1; and most of the superstars will probably apply early as well.
Regarding Ann Arbor, it is a great college town. It does not have local access to major metro areas like some of the other top schools, but it offers a lot of small town advantages. Ann Arbor has easy access to the Detroit Airport, which has direct flights to all major cities. This is an advantage compared with cities like Ithaca, Hanover or Durham, where you will have to change planes to reach many destinations.
Of course, college football is very important at Michigan. Michigan is the winningest D-I college football program, both in terms number of wins and winning percentage. There is a story that Michigan taught Notre Dame how to play football when their train stopped near campus and Michigan students introduced ND students to the game. The atmosphere around campus for football Saturdays is incredible. The town fills up with alumni driving RVs and such several days in advance of the game. Everything revolves around football in the fall. The stadium is the largest in the nation, seating 110,000+ for each home game; and I believe they just invested $100mm+ to expand it. Every game is a sellout and has been for years (decades?) - and each game the PA announcer will welcome you as part of the largest crowd to watch a college football game that day.
Ann Arbor gets cold in the winter. If you have not lived in snow before (I don't mean visited snow like when you go skiing or something), then it will be an adjustment. The good thing is that the snow around Ann Arbor is relatively dry. It's nothing like the lake-effect snow that you get around Chicago that is wet and heavy and will soak right through your clothing. The snow around Ann Arbor is usually light and fluffy, so getting it on your clothes doesn't mean you will soon be wet and freezing.
The Business School occupies a prime location in the center of campus (unlike some others that are on the edge or away from campus). This is great if you want to have a more "college-like" experience. It will suck for you if you don't like undergraduates because there will be lots of them around. The B-schools is right across the street from the law school, and both are near the Student Union. Of course, Michigan is constructing a new building, but that won't be done until after next year. The new building will be amazing, but the old facilities will seem spartan compared with some other schools.
So, as you can probably tell, I like Ann Arbor a lot. The location was a great place to study law (which I believe is more of an academic pursuit), but might be a slight drawback for the study of business because it does not have easy access to a major city nearby. I believe the business school fosters a very collaborative environment and the people are nice and smart without being pretentious.