Originally Posted by Drip

Gold units with same or higher ATK as Edelweiss (4400, dual target):
Peach, gacha reward, 4500, single target
Oxalis, gacha reward, 4500, single target
Star Lily, event reward, 4500, single target
Japanese Iris, gacha reward, 4400, triple target

Of those four, Japanese Iris would be the only one I'd consider "better" than Edelweiss.
Peach and Oxalis more or less on par, mainly due to Edelweiss her relatively low skill activation.
Star Lily just below Edelweiss due to her first passive only buffing one random other squadmember, while her second passive is at "half strength".

Every event girl coming after Mountain Lily is relatively "nerfed" compared to 5* girls coming from gacha. Sometimes by ability, other times by lower stats.
Lavender, Edelweiss and Mountain Lily are as good as it gets for event girls.

Edelweiss is really really good but her evolved ability of +50 spd holds her in line a bit. If she had a % atk power as second ability she would be among the best girls. Basically what Evening Primrose has now Girls with a % power ability can beat Edelweiss in terms of raw power but she still remains a very good all-round 5*, even more so with 4 equipment slots.

I just noticed your helper squad is really similar to mine