>>321758187
I've been really happy with my converted vive wands for FBT. I use one vive tracker for the hip and two vive wands for the feet. If you don't care about accurate foot tracking then you can easily strap the vive wands to your legs. I made my own straps for shoes specifically for the vive wands because I care about rotating the foot. It is pretty heavy but much better than nothing. As for the dongles you can either buy steam controller dongles and convert those(Cannot be undone) or buy these https://www.virtualbuilds.com/product-page/usb-wireless-receiver-dongle when they are back in stock. 
>>321758864
you beat me to it
>https://vrdongles.com/products/watchman-dongle-for-steamvr-and-htc-vive
>$25
fuck i should have gotten my from there.