I'm actually envious of your situation. We don't get BSF here but I have more kitchen waste than my worms can handle so far. With the BSF you should be able to handle a larger volume.

Is your worm factory on it's second tray yet? If so, the BSF should only be getting to your top tray. Your worms may be able to escape down to the lower tray if it gets too much for them. If not, having enough bedding for them to dig down into might help.

Removing them may be a chore. A sheet of landscape fabric covering the top may help prevent flies from laying more eggs in your WF.

A layer of wet shredded cardboard on the surface might help with the heat. The evaporation should cool it off somewhat. A frozen water bottle or ziplock bag full of ice can help too.

Leave the larvae, they'll do more good than harm. Put a frozen water bottle in the middle of the bin, it will keep them cool. I have my worms in my garage, where it gets quite warm during summer. I put a bottle in the bin around noon, and took it out around midnight, repeated for a few weeks.