If you hold your thumb on the MM heading (instead of selecting it) you'll get a pop-up with the option to subscribe. Then mm will be listed under the 'favorite' tab. A little shortcut
As for the second issue, I'm confused as mine has always displayed the op.....
Also, how can I set it so the OP name appears next to the post instead of the ppl who have replied?
Are you talking about which is the first post you see when you open a thread (OP vs last reply)? If so, that's under Loading Behavior in Settings. App vs desktop could also be relevant.