Well, Tilith is gonna break the game some more now, hooray!
So instead of needing 2 Tiliths (your own and a friend's) now you can quite comfortably sustain infinite SBB spam on a single boss with only your own Tilith (Tililth friends are real hard to come by after all). Caution, long team crafty mathy post  
Team:
Cardes(leader)
Cardes(friend)
Tilith
BB filler
BB filler
Mitigator(preferably Narza to help BB fill, Darvan/Shera should work fine too)
 
Maths:
Tilith requires 75 BC to fill her BB
Cardes LS: saves 25-30% of BB (cashback)
Ihsir's Guise: saves 20% of BB (cashback)
BB fillers: Usually 8 BC fill (shida gives 10)
Narza SBB: 5-6 BC when hit
Dandelga: 2 BC/turn
 
Taking worst case scenario of both Cardes only giving 25% BB back we can find out that: 25% 25% = 50% BB back.
Added onto the 20% provided by Ihsir's Guise(on Tilith) means 70% BB filled immediately after you use her BB(start of battle, pop a fujin)
70% of 75 BC req = 52.5
75-52.5 = 22.5 BC required to fill
2 x BB filler (zelnite belfura for example) = 16 BC given
22.5-16 = 6.5 BC required to fill
Dandelga on Tilith (Dual sphere) = 2 BC
6.5-2 = 4.5 BC required without counting BC drops or being attacked (2.5 BC if you have Shida Zelnite/Belfura/Arus, or 0.5 If you have double shida - not advised coz it will gimp your damage output a lot)  
So with 4.5 BC, if Tilith gets hit once, she will fill entirely (Narza's SBB) or if she gains 4.5 BC from the minimum total hits of the team:
2 x 33(cardes SBB) 2 x 18(Belfura SBB, using her instead of Zelnite because his BC buff would push his 17 hit count and whole team's BC generation up way more than 2 Belfuras) 0 (narza sbb) 0 (tilith bb) = 102 BC across 6 units.
 
Even if we say the boss has anti BC drop powers of like 50%, that would be 51 BC across 6 units, with RNG, it is very likely for at least 4.5 BC to go to Tilith.
 
So we can see it is very possible (and in practice against Magress' GGC lvl3, it was not a problem at all, and I didn't even have my Cardes' SBB unlocked)
 
Weaknesses:
- No status cancelling, only protection. - To fix, give all units aside from Tilith a refined gem with their stat sphere. Or really, you probably don't need the Dandelga on Tilith, so give her a refined gem or drevas. Or bring stimulants and holy water just for Tilith. You won't need 5 Fujin elixirs anymore, only 1, nor do you need any heal pots. Also read on.
 
- Low-ish Offensive Presence - Lack of offensive buffs, so this strategy will take a while to win, but it is inevitable (Mr. Anderson). It's really not bad though, you are popping off 4 Offensive SBBs every turn without fail.
 
- Only defensively viable against dark/light bosses - the team is not very tanky against elements other than dark/light due to Cardeses (No HP LS , only 50% mitigation)
 
- Weak against BB sucking bosses - no solution, use BB fills generously and use Fujin/s to sustain
 
- Likely to not be able to vary team much - I have yet to try, (I will soon), but I think if you got, say Lignes, Ulkina, Exvehl, Lunaris to cure statuses, if you have sol creators on everyone (except tilith) or have Rin? Len? The one with the insane hit count/drop checks with Lexida/hallowed orb, you'd be able to maintain SBB tactics.
 
Strengths:
- Against dark/light 90^whaaat?! . g.damn.% mitigation. Permanently.(50% against non dark/light enemy) - Tilith only took like up to total 1k damage in a turn while eating all the Magress GGC lvl3 hits. Insane. Stupidly insane.
 
- Infinite SBB spam without fail = infinite full heals with offensive presence
 
- Don't need healing items, frees up item slots
 
- Only need 1 Fujin to take up a slot, frees up item slots
 
- Don't need Tilith friend.  
 
TL:DR - Slide that Tilith between 2 slices of your finest Cardes, add filling and sauces of a Mitigator and BB fillers. Enjoy your Gourmet game breaking team.
 
For those interested on reading / looking up my double Tilith stats check: here and here
Edit: Other BB fillers will work just as well:
Fei and Fang - gives your team some spark damage too
Lodin - Thunder element and BB fill over time
Kuhla - Atk buff and BB fill over time
Zergel - Atk buff and weakness status (bahahaha)
Another Edit: Turns out you don't even have to have 2 BB fillers as long as you got a boss that hates you enough link
Double Cardes, Tilith, Narza - Maxwell kill.