1-4 in base. Needs the BSS punch to finish Kiria.
Even with the BBS punch she isn't taking Kyria down.
Laxus landed at least two unnamed attacks on her and used Roaring Thunder to KO her. Keep in mind that an unnamed punch from Laxus instantly broke Erza's anti-lightning armour and had Erza herself screaming in pain.
The one hit Erza landed on Kyria wasn't enough to put her down either, and that was a named attack using Belserion + Fire Armour.
There's no way a human Mira is hitting anywhere near as hard as Laxus' unnamed punches, let alone the attack Erza landed on Kyria. Consequently a punch from BSS isn't approaching anywhere near the damage output of Roaring Thunder, in fact it should be more powerful than anything in Mira's arsenal short of maybe an all-out attack from Alegria.
And we aren't even addressing the fact that human Mira is having to do this while Kyria is attacking her, the same Kyria that was easily contesting with Erza and broke her sword.