R1:Renpa(it won't be easy but it won't be his hardest battle).
R2:Renpa again unless Rakukan in the next chapters accomplish some YTW level martial feat(even then it will be debatable)
Ri Boku don't have enough fire power to deal with Renpa,The Battle of Hango confirmed that in a head on head battle,Martial generals will stomp Strategist generals(and While I don't think Renpa is as strong as SBS,Renpa had many things that SBS didn't show(yet)(instincts,Tactics,Memory...)),Honestly in a head on head battle,Renpa will crush Ri Boku and itsn't even close,BNJ isn't enough.
I Know that keisha is a wild card but the heavenly kings also have similar hype(Kyou En literally fighting Ouki and Kyou and Hakuki and Renpa/Kaishibou on par with renpa in raw strengh...),a combination of Rinko and Genpou should be enough for keisha(if not overkill).
KaiShiBou vs BNJ(it can go either way but whoever win will be injured to the point he can't influence the battle any further(similar to whathappened between Akou and Gakushou(which is a W for renpa because BNJ is Ri Boku's strongest piece so trading KaiShiBou for BNJ is good for renpa)
Kyou En vs SSJ.
Renpa will find himsel face to face with a Ri Boku supported by Kaine,Fu Tei,Kotsuminhaku,It will be a miracle if anyone from Ri Boku vassals survived this (BTW,SBS in his charge against Ousen Killed off-screen many 1000/2000 mans commanders(Kei Kyou/Fu Jin/more than likely Hakan and Hakun and many others)The same will happen here just it instead of Unknown commanders,it will be Ri Boku's vassals),It will be a massacre.