Imo time wise a meeting with the Devil lord doesn't seem like it would take up more than say 40 mins of the Corum's time in game, so I say just get it out of the way first so the Group doesn't have to deal with a pissed off Mephistopheles. Not saying you guys couldn't take him in a fight right now, but you kinda need him to fight in the blood war, not recovering from wounds. Plus you COULD gain some useful information from him. It just seeems to me that putting the talk with Mephistopheles on the back burner right now can't be justified IMO and seems silly to do, and it wouldn't take up alot of time. Admittedly I could be completely wrong and Mephistopheles could ambush you when you meet up with him, but there is no concrete evidence to prove that right now. Plus if you all (sans Lincoln) are really worried about it you can all try praying to your various gods for Divine protection (Excluding Brandis, Crom doesn't listen.), Hugh could even put a offering to Avandra for better odds if he wanted to. Hell if it works out you might be able to call in some elemental wind spirits from Akadi / angles from The Platinum Dragon. All in all is doesn't hurt you either way to pray to your gods for help. So besides the meeting what I'd like to see happen is...
1. Deomin's Quest<- Can you say building an army of Wind elf elementals!? I say fuck yeah! Plus Deomin need's to find a girlfriend >.> (Brandis and Arora are already married, Hugh has all the Whores, and Wrenn has been courting Freda since Paragon Tier. I feel like Deomin is being left out honestly.)
2. Meeting with the Raven Queen<- real close second, I'm very interested to know what could come out of this meeting.
3. Use that key you got and try to find time's Arrow<- Upgrade for Hugh? More RP for Sam? Always good.
4. Search for the rest of the Ruby shards<- you already know where some possible locations are.
5. Figure out the ship docking thing and or get info from the other librarys.
6. Make Blackwood get his shit together. Nuff Said
7. Whenever you get to Dark World, start searching for the Crimson Stone Rod.<- 100% upgrade for Lincoln
8. MOAR Seldi time? Other dolls? MOAR Mindflayers? The possibilities are truly endlesssly evil!
9. Dig up some info on Hasten's Origins?
10. Recruit More Doppelgängers for your Master of Secrets to use?
11. Investigate possible mining operations you could do on where that crystal flame Cavern is in on your time line? Supposedly Far underground? Possible upgrades to your ship? Make it sentient? Living crystal hull? Could Deomin turn them to wind crystals? Sounds pretty epic if you could have a Wind infused crystal shardmind ship siding. Have the shardmind obey Deomin? New weapons for your thunderstrike army? Armor perhaps? Or just more gold? It would be kinda boring if all you get is gold imo. I'd like to see more ship upgrades personally. Give that Tiefling girl of yours something to work on.
Just my two cents. Hope I didn't step on anyone's toe's at the saying goes.