"Have any of the other molecules been synthesized and tested in any way, or are they on paper only?"

Synthesized and many tested. From October 2016 (surely way more advanced now almost 4 years later):

https://agoracom.com/ir/Resverlogix/forums/discussion/topics/675327-highlights-of-webast/messages/2114589

"New compound(s): Milestone slide had the box checked off for "Confirm a second clinical compound IND candidate" with the added comment "Seven compounds chosen for follow-on testing." 2400 synthesized compounds in library. RVX-206, RVX-641, RVX-2101, RVX-2113 (Just happen to be 4 of DM’s favorites). Complement, Calciphylaxis, Autoimmune, FSHD/DMD, Pulmonary."