Will bisect not get confused if you change the commit range it's testing as part of running it? Also cherry-picking might still generate conflicts.

No: you would cherry pick the change needed to bring in the test code, run the test and decide whether it is "good" or "bad". Then before running "git bisect good/bad" you would eliminate the cherry-picked change with "git reset --hard HEAD^".

You can also "git cherry-pick -n" to only apply it to the working directory, with no commit, and then "git checkout -f" is an easy cleanup.