Apparently it’s the best of 5 one-on-one or two-on two, or 1 vs 1 2 vs 2, 3 vs 3 etc... matches. First side to win 3 battles wins. However Freya allows Hestia Familia to use a couple of ringers. Team Hestia is Bell, Mikota, Welf, Lily, Ryuu (who gets a level 5 blast up by joining Hestia’s or from her old goddess). Hestia’s ringers are Aiz, Rivera, Lafiya, and some mystery character (presumed to be Bell’s aunt Alfia who was a level 7 from Hera Familia.). Team Freya is obvious.

Mikoto, Welf and Lili are outright usless. They mean nothing against a Level 5, the lowest level of the Freya Familia executives.

Ryuu would be a new Level 5 at best, which means that in power she would be losing even against a single one of the Gulliver brothers. Moreover, in her fight with Ais in SO10 it was said that due to no longer fighting in the dungeon like she used to and Ais still did she also lost in technique. All of Freya Familia executives have been active for more time than Ryuu and non of them have retired like her, so she also loses in that area.

In summary, she would be able to give some actual fight, contrary to the first three, but barely some, at the end she would be defeated relatevely easy. And if it is a Level 6 instead she would lose quicker.

Finally, Bell. Even if we assume he does level up before the fight he would be around a mid Level 6 at best. He could face a single Gulliver brother but a Level 6 could defeat him.

So no, individual fights would just end up with all of them defeated.

And no, Alfia won't appear to save the day. She is dead, the story made it pretty clear.

If you really want to ignore the terrible condition she was left in, her mortal illness, the damage of the fall she threw herself to, the giant pit of fire at the bottom of that hole, and her dead wish (cause if someone throws themselves to something that is a sure death it is clear they want to die) let me remind you of something.

In a tweet that he wrote regarding the IF story of Alfia Oomori outright said that in that timeline she would live a lot of time and managed to reach the current story. He literally confirms that, for someone with her disease, just reaching the time of the main story would be surprising.

And that is something she would have managed to do only due to the "mother power" as he calls it, something she only got from going with Bell, which she didn't do in the actual story.

Moreover, he said "in this world", meaning in the one of the actual story she didn't.

Put more simply, in the timeline of the actual story she didn't manage to do so. She is dead, gone, regardless of how much you dislike it.

In case you don't believe here is the tweet: https://twitter.com/fujinoomori/status/1299673816260460544

Ask someone who knows japanese or use a translator, whichever you want. The fact is pretty clear.

@Rigel31415 i am pretty sure that other adventurers first and last level is diffrent for example ais firs level last stats araound 2900 and the last one is 3600 İTS same for hedin to bell can defeat High level 6 but it will be head to head or bell will has the upper hand and bell last fight aginst hedin at this volume Wasnt Bell slowly gaining the upper handbut in the end bell lost the fighting sprit and hedin just kick him