Before I found this forum to ask, I did email the same question to HTC Cust Service/Support. Fwiw, here is their answer. Slightly different taps, same effect:
I will be happy to assist you with adding the Favorites widget back to your Rezound. This is very easy to set up. You will want to tap and hold on an empty spot on your home screen then tap on Widget. Once the options appear, you will then select People. Now you will be able to choose the view you would like to use. You will also be able to choose which Group you would like to set as your favorite. Once you locate your desired view you will then tap on Select then place on your home screen. This will most likely place on a random spot on your homescreen, if this happens you may tap and hold on the widget and then drag to the desired space.
And they also went on to clue me in on my original wrongdoing so I wouldn't make the same mistake again:
if you wish to remove an individual from the Favorites widget, you will need to do this within the contacts. You will need to access your People application then choose the contact you wish to remove from Favorites. Once you are viewing the contact, you will tap on Menu> Edit. From here you will locate Groups (there will be a scroll box with it). From here you will choose None or leave it blank. You would also follow this process to add new contacts to Favorites. Please do not hesitate to reply or call if you need additional assistance and thank you for being a HTC customer.
That last part seems to be a rather dumb design IMO. If I can add (+) a favorite contact to the widget, I should be able to remove (-) one as well from the same context. Oh well.. Maybe I will remember this next time.
Pretty good customer service. That's refreshing.