Can someone please help me?

tu see, I'm going to this new Haunted House for Halloween. It's called Pennhurst, tu probably heard of it if tu live in the state of Pennsylvania in the US. Well, my mother let me invite three people; my cousin, Angel, and my one best friend, Arielle. There's one más person who can come with us, but the problem is....there's four other people I want to invite, but I can't decide who.

Their names are Diana, Diamond, Toni, and Jen. Each comes with their own pros and cons;
1) Diana - She's my segundo best friend and is always invited to my BD parties, but she may have Band that día so I'm not sure if she can make it.
2) Toni - She's very fun and nice and I would amor to invite her, but her, Arielle, and I sit with two other girls that I don't know very well but are very nice (and funny). I don't want to be rude and happen to invite two people at my lunch table, but not the other two. :(
3) Jen - I was never able to make it to the things she invited me to due to family problems, and something was going on with her during the summer so she didn't go to my BD party. I thought that maybe if I invited her to this, it could make up for something.
4) Diamond - I met her this año in my Geometry class, and I want to take an opportunity to know her a little better.

I'm very stuck with this, and if anyone is willing to offer some consejos o even suggest who I could invite, feel free to do so. :)

Thanks!