I would remove a couple of your faucets, and tear them down to do an in depth visual inspection to check for anything that could be a nucleation site. There are have been some historical reports of intertaps with poor castings and poor finishing with rough surfaces.
I have 1/4" ID bev seal ultra 235 tubing on my 14 faucets with perlick 650ss flow control faucets from the coffin box. My setup is a bit unique, I suppose. I have some lines that are a bit more foamy than others, but I am generally satisfied with the pour that I get, considering that the shanks and faucets are at room temp in the unchilled coffin box from the walk-in cooler.
I have the 650ss because of the 1/4" ID tubing (I had converted to 3/8" OD tubing fittings many years before, so I was committed to that tubing OD size, which meant I needed to use 1/4" ID bev seal tubing). Since I was using 1/4" ID tubing, I needed the flow control in order to be able to have the necessary restriction necessary for decent pours without having 50 ft of tubing per faucet (which for 14 faucets, is a LOT of tubing).
All that to say, if your flow control faucets are working as they should, you should be able to easily balance your system, so if you are having issues, you need to examine your entire setup to ensure that you aren't following a red herring.
I will say that an issue that I have run in to is with debris flowing through the lines that clog the flow control mechanism. This causes reduced flow and increased foaming.
Also, if you have foaming in your lines themselves, then you need to also check your kegs, the dip tube, poppets, disconnects, etc. If the foam is starting at the keg, that will cause foam all the way through.