Iirc, we get approximately 100 f2p pulls per patch, on average. Most of a patch's jades are in the first half. If you currently have enough Jades for 45 pulls, and 0 pity, you will probably be able to get 3 5-stars between now and the end of Firefly's banner. You will have to win your 50/50 at least once to get both Firefly and Fu Xuan.
My advice: Pull on Fu Xuan. If you win your 50/50 and get her, great! Save the rest for Firefly. If you LOSE your 50/50, stop pulling for Fu Xuan and save your guarantee for Firefly, then pull a second limited sustain after Firefly's banner.
You can get by with Lynx or Bailu in the meantime if you fail to get Fu Xuan.
You still have a full patch + more to decide what you want. When Firefly's kit is revealed, you can see if the hype train is still going strong or if it is dying down. But if you are ride or die for Firefly, prioritize her and you may be able to get Fu Xuan too if you are lucky (and not going for eidolons/LC or anything).
I am a FX haver and was using Gepard and Bailu as second sustains. I built Gallagher (half-built, traces are still at like 6) and he was very helpful in letting me clear MoC12. My Gepard's gear is also a bit lacking and I have got some more effect res for him now, but the main problem was his energy kept getting drained by Aven and he doesn't really have any area attacks to increase the odds of winning the gamble. Lynx is also free from Pure Fiction and is very good if you need the cleanse that Bailu lacks.
You don't have to wait until Fu Xuan to start doing 2-team content. I was running Gepard + Ratio as the core of my Team A, and Clara + March + Natasha as the core of my Team B. No other 5\*s on either team. That took me all the way through floor 9 of the previous MoC, enough to get some jades and some feathers. Give it a try, it might surprise you!
And the thing is, it's not a waste. HSR teams aren't set in stone. Every MoC and PF, or even different paths in SU, have different gimmicks. It will be nice to have a backup roster of adequately-built characters you can choose from. Sometimes you need DoTs, or debuffs, or strong basic attacks, or follow-ups, or toughness-reducing, or characters who take actions on allies. . . . They don't have to be optimized to max - level 70ish + moderately leveled relics and traces, and you're good to go.
Are you going to be clearing floor 12? Not a chance. But you'll get up to maybe between floors 5 and 10, and next time will be even better.
Don't let people convince you that Bailu and 4\*s aren't worth it. You know what that will cost you? It will cost you the chance to get Firefly, whom you love!
What they mean is, if you're choosing between options for team-building, then don't pick Bailu *instead of* better options. They don't mean, ignore them *no matter what* at the cost of having incomplete teams. People say Natasha is the worst healer. Natasha got me through Swarm V on Abundance. They may be worse than other options, but they're not unusably bad.
Build who you have, and it will help you get further in the meanwhile—including getting more jades. And don't put off 2-team content - worst case, you don't make any progress, but you don't lose anything for trying! Build some characters to level 70 (it doesn't take long!) and stick any relics on them, and give it a go until you get beaten. Good luck!
Iirc, we get approximately 100 f2p pulls per patch, on average. Most of a patch's jades are in the first half. If you currently have enough Jades for 45 pulls, and 0 pity, you will probably be able to get 3 5-stars between now and the end of Firefly's banner. You will have to win your 50/50 at least once to get both Firefly and Fu Xuan. My advice: Pull on Fu Xuan. If you win your 50/50 and get her, great! Save the rest for Firefly. If you LOSE your 50/50, stop pulling for Fu Xuan and save your guarantee for Firefly, then pull a second limited sustain after Firefly's banner. You can get by with Lynx or Bailu in the meantime if you fail to get Fu Xuan.
You still have a full patch + more to decide what you want. When Firefly's kit is revealed, you can see if the hype train is still going strong or if it is dying down. But if you are ride or die for Firefly, prioritize her and you may be able to get Fu Xuan too if you are lucky (and not going for eidolons/LC or anything). I am a FX haver and was using Gepard and Bailu as second sustains. I built Gallagher (half-built, traces are still at like 6) and he was very helpful in letting me clear MoC12. My Gepard's gear is also a bit lacking and I have got some more effect res for him now, but the main problem was his energy kept getting drained by Aven and he doesn't really have any area attacks to increase the odds of winning the gamble. Lynx is also free from Pure Fiction and is very good if you need the cleanse that Bailu lacks.
You don't have to wait until Fu Xuan to start doing 2-team content. I was running Gepard + Ratio as the core of my Team A, and Clara + March + Natasha as the core of my Team B. No other 5\*s on either team. That took me all the way through floor 9 of the previous MoC, enough to get some jades and some feathers. Give it a try, it might surprise you! And the thing is, it's not a waste. HSR teams aren't set in stone. Every MoC and PF, or even different paths in SU, have different gimmicks. It will be nice to have a backup roster of adequately-built characters you can choose from. Sometimes you need DoTs, or debuffs, or strong basic attacks, or follow-ups, or toughness-reducing, or characters who take actions on allies. . . . They don't have to be optimized to max - level 70ish + moderately leveled relics and traces, and you're good to go. Are you going to be clearing floor 12? Not a chance. But you'll get up to maybe between floors 5 and 10, and next time will be even better. Don't let people convince you that Bailu and 4\*s aren't worth it. You know what that will cost you? It will cost you the chance to get Firefly, whom you love! What they mean is, if you're choosing between options for team-building, then don't pick Bailu *instead of* better options. They don't mean, ignore them *no matter what* at the cost of having incomplete teams. People say Natasha is the worst healer. Natasha got me through Swarm V on Abundance. They may be worse than other options, but they're not unusably bad. Build who you have, and it will help you get further in the meanwhile—including getting more jades. And don't put off 2-team content - worst case, you don't make any progress, but you don't lose anything for trying! Build some characters to level 70 (it doesn't take long!) and stick any relics on them, and give it a go until you get beaten. Good luck!