Here is the lowdown.
1 - TVii will work, from a programming guide / change your channel standpoint, with all major providers including DirecTV, Comcast, Charter, AT&T, etc.
2 - While the DVR interaction has so far only been announced for TiVo, in the interview linked below, the guy seems to intimate that they hope to have it working with other providers later. Even if it is not there day one, it can be updated/patched later. He actually says "Yes" to if it will work with DirecTV dvr, then backpedals. Not sure if he misunderstood or that they just aren't ready to announce it.
Video:
http://www.youtube.com/watch?v=cStP8vTWXoo&list=UUcfVIkwtBbunmSgELQF8DWg&index=3&feature=plcp
(lots of other Wii U interviews I hadn't seen before too by that guy)