I dont belive that JF is going to fit on your situation. Khagan is, imho, the worst one off the vanilla reds and Quintus is another one, that unfortunatly for you is among the worst this game has to offer. So, while JF would be a really good improvement, you will also have to use another 6 rings which I dont know if you have at hand.
Now, Sunday and Telluria she can be a really good addition to any team. For you, the main problem I see is that you have a strong Melendor so you would be using a x2 Green in your defense, but while not ideal you would be replacing Quintus for Telluria making your team MUCH MUCH stronger, even while factoring the double green.
Also, pulling on Sunday will give you a good chance (the best one you will ever have: because s3 pool is shallow right now) of pulling Freya or Heimdall (important thing to consider for him. is that I belive that Alberich is not comming back in Atlantlis Hotm rotations, so that leaves only MN once x year, until developers bring back old HOTM in a new mechanic). And Freya seems to be a really good hero player when going for Minions (which Telluria a hero that works around that), only problem with Freya is the need for 6 Tabards… seeing how you used them on Quintus, not sure if you have the spare ones for her.
So if WAITING for Valhala portal at the end of March is not an option, and waiting for what I belive to be in 2 months an Atlantlis cycle with GM and Seshat is not an option. I would say you get better value, by trying to summon on Sunday.