It was undecided Republicans, and even then 25% didn't view the speech favorably. That seems to be around the same level of non-support he is getting from Republicans in most polls.
No. It was speechwatchers of all political stripes. Of course, for the RNC, this is going to skew Republican. You'll have a pro-Democrat sample for the DNC.
Full results:
CNN/ORC Poll of Trump Speech Watchers
Overall Reaction to Trump's Speech
Very Positive 57%
Somewhat Positive 18%
Negative Effect 24%
In what direction will the policies proposed by Trump move the country?
Right Direction 73% (was 60% pre-speech)
Wrong Direction 24%
How did Trump's speech affect your vote?
More Likely 56%
Less Likely 10%
Not Much Effect 32%
Source: CNN on TV. No link yet, best I can tell.