I’m really not getting the collective angst against this idea
DD has been in the “B list” of friends in a similar situation & she’s also been in the “A list” group. On neither occasion did she feel left out or smug that she was included. They are not 5 anymore, imho way past the age to learn that you don’t always get included in everything & that’s still okay & doesn’t make you less of a person, just that sometimes allowed numbers do limit the number of possible invitations. It would be different if your DD used it as a power tool amongst her friendship group, as did happen to DD in one occasion, but that’s unlikely.
As for a limo is tacky, isn’t a lot of what kids this age like, tacky
isn’t the party for them, nit the adults, therefore so what if it’s tacky🙄
As kids get older, Birthday treats become more expensive & with popular DCs often impossible to invite the whole friendship group & as in life with adults, some will be closer to the OPs DD than others, that’s life why make it into something it’s not & use it to teach your DCs that it’s not about them, but the situation & not to take it personally, they will be included in the “A List” group at other times. IMHO it’s a better way of dealing with it, than feeding the self entitled idea that your DCs deserve to always be at the top of the invite list. Doesn’t exactly prepare them well for life does it.
If you want to do this in a more fair way though, you could try what we did one year when DDs main birthday treat meant she could only take one friend with her. They pulled straws & the winner came along & the rest all came along to a lest expensive get together