Downloading the index files is unrelated to the ansvr port. The port has to do with how SGP and ansvr will communicate. Are you able to open the link http://127.0.0.1:8080/api/config as described in the ansvr install instructions? If so, then the port number is fine.
If you had trouble downloading the ansvr index files, could you be more specific about what you saw that indicated you couldn’t connect to download the astrometry files? A screen-shot would be helpful.
Even though you are planning on using PlateSolve2, it is still a good idea to install ansvr to use as the backup for those cases where PlateSolve2 cannot solve or when no location hint is available (“blind solving”).
Andy