We really cannot guess what the insect may be. We recommend either trying to gather a sample of the pest for a pest ID or calling a pest control operator in to give a free or low cost inspection to help you make the pest ID. Once you know for sure what pest you have, you can choose the correct treatment method.
We recommend doing the treatment with the Fipronil or Altriset first, waiting 90 days and then following up with the Boracare. This will allow the termites to go back to the colony with the active ingredient on their body and pass it around the colony causing the entire colony to collapse. If you treat with Boracare first, you risk only killing the termites present and not getting rid of the entire colony.
Since all surfaces of the wood need to be treated, we would recommend you remove any item that is blocking the application from reaching the wood. You should drill through any layered beam to get the solution all the way to the next beam when necessary.
Boracare is specifically designed to be applied to plywood and any other raw wood surface that hasn't been stained or finished with anything like paint or a sealant.