My co-administrator sent out an email last night (from the site where she clicked the names) and the email went out from me. Can we make her emails come from her?

Can't think of a good way to answer your question.......

Ok seriously, it's going out from you because you overwrote the default, which is to send the email from the sending Administrator. I.E. Go into your Preferences area and look for this:

"Check this box if you would like emails sent using the "Email The Class" feature to come from the Site Email Address above instead of the Sending Administrator's email address"

Ya done checked the box! So, all emails are going to go out from you, and not from the sending Administrator, until ya done deselect that box.

Thanks. Really I was just trying to get your attention so you would answer my question first! Good night

I am assuming that if want I change the signatures in the automated emails from the Admin's name to "Reunion Committee", I would just delete the "$ca_first_name$ $ca_last_name$ $ca_married_name$" in the body of the emails? Is this correct?

That's correct. Any variable can be deleted and replaced with regular text instead.