Hi everyone,
@rparadiso was able to solve the greengenes branch length issue in a separate topic — see here for a few different solutions:
@cjone228 that topic lists some other options — opening and manually modifying the file, or running a python script in the bash shell (command line), so there are a few options to suit whatever you feel most comfortable working with.
Please post to that topic if you have any follow-up questions or run into any issues with fixing your tree(s).