Hi,
Well, I’m afraid that none of this is possible at this point, at least not without major modifications to the current code.
I am working on a solution for front-end ordering filters, it should be available within the next two patches, although it depends a lot on the test results as wel. The custom field ordering you can set on the ordering panel only affects the post types. There will be additional two options there in the upcoming release to set a separate ordering for user results as well.
I’m afraid there is no quick bypass solution/custom code for this, as the implementation for ordering by custom fields requires major changes to the main query as well as other files.
The ordering by custom fields for user results will be definitely implemented in the upcoming release, front-end filter for ordering probably in the one after that.