Could be an issue with windows 10. When you open the Logitech control center from your tray, do all webcams show up and are selectable from the dropdown menu? If not, I think it is a driver / USB host problem. If all three cams are shown correctly and are selectable, they should also work in xSplit - if xSplit still freezes, it may be a problem with xSplit (bug, version, incompatibility, etc.).
I use 6 Logitech webcams (910,920, 2 x 525, 2 x 270) plus 2 noname cams all simulteanously in xSplit. It crashes sometimes, but most of the time works perfect. When I transport the equipment to different locations, sometimes the cams are not recognized in xSplit any more. Normally I can solve this by using different USB ports.