Regarding recovery from simultanteous bilateral THR, everyone is different, but here is my experience:
I was 53 yrs old, very athletic and fit right up to surgery. I had MIS posterior also. I have Stryker titanium/poly. Fantastic surgeon. Great home support, so I had it all in my favor.
The surgery itself was a little more complicated than anticipated, hips were worse than they looked on MRI but I made it thru with both sides done in about 4.5 hrs. I had a spinal so was very aware of what was going on.
My recovery was extremely fast, I was home in 2 days and forgetting to use my crutches within 4 days. Within 2 weeks I was starting back to work in my dog boarding/grooming business. Within a month I was starting to hike the Long Trail, lifting weights, easy bike riding, etc. Within 6 months I was back to any and all activities I wanted including kayaking, downhill +x/c skiing, horseback riding (including jumping), some jogging, mountainbiking, rollerblading, whatever. After 1 yr (last May) my xrays looked so good my wonderful OS lifted all restrictions and said "Go for it". I absolutly love my new hips (and my OS)!
It sounds like you are pretty fit and willing to work hard at your rehab. That will help more than you can imagine. If I can give you any advice, start right now with strength training to get as strong and lean as you possible can. I am sure that made a huge difference in my recovery.
Baseball-I love it. I have 2 sons that played all thru college, in fact the middle son went to a D1 school on a BB scholarship and had a great ride, graduated with an engineering degree and was recruited right into a great job. I coached BB up to the high school level and loved every minute of it. However, playing baseball, at least competetivly, will probably be pretty tough. I doubt you will find a surgeon that would be happy about it. If you are coaching, it probably will be fine very quickly, certainly by next spring. But do not count on being able to sprint often, turn/pivot fast often, slide, turn double plays, etc without putting lots of wear/tear on your hips as well as possibley damaging them or dislocating. However, the stronger your muscles, tendons, ligaments are, the better your hips will work and be protected. I am able to safely do more activities than the average THR because of my strength and my surgeon is very comfortable with a long hip life even with my high activity level. Only time will tell how you make out, but most likely you are gonna love your new hips too! Have fun with the baseball!!
Andrea