As I mentioned earlier, a lot of times an SMC/PRAM reset doesn't help at all. But considering that you have a new trackpad and it's easier to do that than opening up the computer, I would make sure to do that. Some people report that they had to do a SMC reset multiple times. That wouldn't explain why temperature sensor problem, though. If after doing the SMC reset, things aren't work, it's a either: 1) defective trackpad/keyboard, 2) improper installation or 3) something is not right with the logic board.
1. Defective trackpad. Did the trackpad have the part #'s 922-9063, 922-9525, 922-9773 as part of their description? Those are the Apple part #'s - you probably didn't get Apple parts but the description should have had that as the part they're replacing.
2. The trackpad installation is pretty straightforward - the keyboard seems to be difficult - 50+ screws on the keyboard. Is that right?
3. I think the most likely place for problems with the logic board with regards to the trackpad is the connector. Take a look at
https://www.ifixit.com/Guide/MacBook+Pro+13-Inch+Unibody+Late+2011+Trackpad+Replacement/7664
If you look at step 8, there may be a liquid spill indicator to the left of the trackpad connector (the thing with the white dot). Do you have that in your computer - does it seem to be a LSI? Is it still white? In step 10, you can click on the picture and then magnify it - does your connector look as pristine as the one in the picture?
You can also try disconnecting the USB mouse and see if the trackpad works (but that wouldn't explain the sensor issue).
If all 3 of these things are fine - that's a tough one - you're going to have to decide whether to proceed or not. The trackpad installation is pretty straightforward. If the fan was running on high constantly before the trackpad replacement, I would think that there's something wrong with the logic board because it wouldn't be that likely that both trackpads had the same problem. If the fan running on high only happened with the new trackpad, you may want to try putting back the old one, running diagnostics and seeing if you get the same issue. If you don't have the same error, then there's a good chance the sensor in the new trackpad is defective and it should be returned. That would also confirm that the error code you got is the sensor in the trackpad.