Mordru is just being reintroduced in the LSH reboot. Universo and Time Trapper have not been reintorduced^([sic]) yet so they're unlikely. Phantom Stranger and Destiny maybe be trapped in the Vertigoverse which may make them unavailable. Dr. Fate isn't around any more. Brainwave and Ultra-Humanite are JSA villains so DC will deny they ever existed. Shazam will probably wind up being an Ally if he's used. Same with the Chief.
Source: wiktionary