Can anyone confirm if the Canon XH-a1 can benefit from these recorders besides having a tapeless workflow?

Both the Nano and the XDR were designed for camcorders with an HD-SDI output port. The Nano also can accept output from a cam with HDMI output. As the subject camcorder has neither of these outputs, I don't see where you would feed these flash recorders.

I wonder though if there were a converter for your component output to HD-SDI if you would then gain the color space of 4:2:2 and higher data rate recording?

If you could upgrade your A1 to an XHG1 then you would have the same familiar camera but with the needed HD-SDI that bypasses the internal HDV compression.