1. I've heard some third-hand comments that there is an ice skatng/hockey rink somewhere in MVD. Does anyone have any insight into this, and do they actually play hockey?

2. Any chance that anyone knows of softball games or (competitive, beer-league, co-ed or otherwise)? Is there a baseball diamond, makeshift or otherwise in UY?

Hi MvdCanuck !

There was an ice rink at Montevideo Shopping Mall.
The rink belongs to a local company whose name is FANTASY ON ICE.
FOI is trying to promote the ice skating in Uruguay.
The rink was at the mall for 6 months.
I think FOIs plan is to make a tour all along the country, so the rink would return to MVD in few months.
Anyway, you can watch some guys playing hockey on roller skates at Parque Rodo, just across from MERCOSUR HeadQuarters (former Parque Hotel). They play by the evening.
In addition, skating and hockey tradition is quite old in Uruguay, so maybe, while waiting the return of the ice rink, you could try at some "Hockey sobre Patines" club, like -

http://www.platensepatinclub.com/academia.htm
http://ligauruguayadehockeypatin.blogspot.com/

Regarding the "softball", I guess we "natives" have no idea what softball is.
No baseball diamond either, but I have watched some guys playing baseball (or what I assumed it was baseball) at Parque Rodo on Sundays afternoon.