Here's a pic I took back in April of some female minis next to a 1:43 scale car.
Hasslefree Tiriel; Dark Sword Amazon; SJB Alejandra (CMON); I-kore Commander X; Grenadier female evil warrior (1987).
I didn't have a Wyrd mini at the time but do now so maybe I'll do a new line-up. - I've since held Taelor next to the car and she looks just like she's giving directions
anywho, you can see that the middle 3 all look about the same height, but if you look closely, the Dark Sword mini is standing on a hill so she's actually smaller. Tyriel looks shorter, but she's not standing straight, so hard to tell, but "scale" I would say is the same because not all women are the same height IRL. That would go for Commander X who, if you look at her eyes and the fact that she's on tip-toe is still shorter than Alejandra.
Now the obvious difference is the old Grenadier mini who is actually 25mm from the soles of her feet to the top of her head. She appears to be a dwarf to these others.
So the short of it is, I think I'd be okay if the 4 newer ones were described as the same scale, but if the old one was included I'd be pissed off. (by the way, most of my minis were the old size and when I got back into collecting boy was I annoyed)
What about going for a more vague description such as "standard table-top gaming scale"?