Some are, some aren't
Of your two I would say Ongh is worth it (viable in halfs and mono Jungo and isn't as frequently banned as Troompah) Plus Jungo is insanely strong
Bogdan...iffy. He is rarely let loose, I wouldn't reccommend unless you are wealthy enough to just have the cards. And without him Freaks are nowhere near as good
If you're really serious, yes. It's good to have the cards at hand all the time, so whenever a clan is clearly dominant in ELO you are prepared with the cards to abuse it. I know some players who sell cards as they are banned for the week, buy the unbanned cards, and repeat the process. This loses clintz as time trickles down, and most of their ELO winnings end up sustaining that loss.