Did the reflash on the Variax (JTV firmware re-install via Line6 Monkey), and it worked! Upgraded from version 1.7x to 2.x. Thanks for the suggestion! It was fairly tricky to save and reload my presets, but I eventually got that to work, too.
Now ALL of the features between Variax and Firehawk are working - and I didn't have to reflash or update the Firehawk at all.
BTW, the gig Friday night went great. I went straight from the Firehawk into the PA, but also used my amp just for monitoring. Sounded awesome.
Thanks again! It's a new era now... Next week's gig should be even better!