Good news first: it works quite well with the TI. I will test with an HDMI video capture later for the fun.
Bad news, my Onkyo receiver is finicky about its inputs and often causes problems for HDMI sources. My Intel NUC media computer, for instance, video playback will lock up any time anything changes with the Onlyo (like turning on the second video output, etc.) When the retroTINK is idle it displays a color bar pattern in 480p. Turn on the TI and you get the power-on "honk," then the Onkyo flips out for a few seconds before bringing up the screen. Afterward there is no sound.
I tested directly to an HDMI monitor and everything works fine. As well, this does not happen with the NES. Bummer. I might see if this is something which can be fixed in the retroTINK. The Onkyo works fine for composite input on its own, but it does treat the signal as interlaced so the standard tearing applies.
Otherwise, for portable purposes this will work for me.