[14.2] Jazz 2 versions

Jazz is coming back, and doing pretty good. On top of that, you can play these two variants, both are okay, though the second one might be able to reach a better spot. The Superfans give a free item and are easy to play together, and they are cheaper, making them easier to find early on. The downside is that they tend to fall off in late game, when Lillia isn't a decent unit anymore, and Kennen, despite his best attempts to stun some units, will do little more than give Guardian to Neeko. Kai'sa also struggles to do her job at that point.

The other variant has the benefit of including better, stronger units, but the downside of being way more expensive and one less trait. Note that you can transition from one variant to another, though it might be tricky since you won't want to remove your Superfans if your replacements (at least Sett) aren't 2*, and most of the time, you won't really be able to afford saving gold for replacement units. I'd recommend the second variant if you've been able to get a Heartsteel start. The more Hearts to be converted into loot, the better.

In my opinion, you'll want either Jazz Bard, or MF regardless of her Headliner proc.

If you have Dazzler Bard, adding Lux or Ziggs won't be as useful as they will add either EDM or Hyperpop, but Dazzler will already be on. The Jazz proc, on the other hand, will allow you to get to 4 Jazz with Lucian, or at least more traits for your Jazz bonus.

As for Miss Fortune, if you've got Jazz, again you'll be able to reach 4 Jazz, but if you've got Big Shot MF, settle with it. Indeed, it is now made impossible to tweak the Headliner offers in your shop by buying and selling a unit if the Headliner proc isn't the one you want. So you won't want to waste who knows how much more gold just to get Jazz MF. You'll then want to either play 4 Big Shot or not play Ezreal at all and keep items for Lucian. Ezreal would be able to damage the backline, but Lucian is now a very good unit since he isn't bugged anymore. So I'd say both plans are valid.

If you've got Bard as your Headliner :

If you play with Superfan, DO NOT GIVE HIM A SHOJIN'S SPEAR ! Indeed, his Superfan item is Adaptive Helm, and the 10 mana he'll get every 3 seconds will disrupt the mana gain from Shojin. He'll always waste some mana. Instead, you can give him more Adaptive Helms, or a mix among Blue Buff/Rabadon's Deathcap/Spellcrit/Morello. I'd say one more Adaptive Helm is fine, two might be overkill and once again lead to him wasting some mana. Morello will allow him to apply Burn and Wound on many units if he has stacked enough during early stages, Rabadon's Deathcap and Spellcrit might allow him to kill a few units right from the start of the round.

If you're playing him with Superfan, THEN you can give him a Shojin's Spear, but then again, do not give him an Adaptive Helm or a Blue Buff with it.

If you're playing MF as your Headliner :

Superfan will give her a Deathblade. Regardless of whether you play her with them or not, you'll want a Last Whisper on her. You can give her a Guinsoo's Rageblade, and if you don't play with Superfan, an Hextech Gunblade will give some sustain to your team.

Regardless of whether you play with Bard or Miss Fortune as your Headliner, most of your game will be played out at level 7. Indeed, either you'll have Bard first, and you'll want to be level 7 to have better odds to get Miss Fortune too (as well as other 3 cost units such as Ekko and Neeko or Sett and Lux), or you won't, and you'll want to be level 7 to have better odds to get Miss Fortune as your Headliner. Odds for 2 cost units are about the same between level 6 and 7.

If you play the variant with Heartsteel and EDM, Three's a Crowd is also a good choice, since you'll have four 3 cost units, giving all your units +300 Health, amplified by the Jazz bonus.

Also, What the Forge can be a makeshift solution if you've got trashy items, since it'll turn every completed item, regardless of the result, into an Ornn Artifact, and give units 110 Health for each Ornn Artifact they're equipped with.