Thinking hard here …
Eva Grub?
That’s it! “Grubb,” with two Bs.
GILLIGAN: Well, it’s not the greatest name … but you can always change it!
So I get a B+ then. 
I’ll take that; thanks!
(I have to admit that @Beckdawrek 's answer jogged my memory. I still had to do a little thinking, but many thanks, Beck!)
I got a C-
Here’s a really tough one:
Name the two girls in the original (unaired) pilot and their shared occupation.
Extra bonus points if you can name the actresses who played them.
Nope. Can’t touch that.
I’d guess they were waitresses.
Nope, a bit more skilled than that. Still, the original theme song said they were “taking trips that they could not afford.”
Hmmm?
I’m going to guess secretaries, or airline stewardesses.
Yes, they were secretaries! They were also (according to Sherwood Schwartz) “too much alike,” which is why they were replaced with Ginger and Mary Ann.
The names of the two are tricky…
Is there a Mr. Grubb? Or is he on vacation?
No she was an forlorned and left alone old maid
Unfortunately, no. 
To the best of my recollection, Eva once went on a blind date. After a few minutes, the guy said he had a splitting headache and was going home.
GILLIGAN: Well, maybe that’s where he kept his aspirin.*
*Wasn’t this also a gag on Cheers? It sounds like something Coach or Woody Boyd would say.
Do you remember what Uhura’s response to this was?
“In this century, we’ve learned not to fear words.”
“Ginger” and “Mary Ann”?
Maybe they were twins or at least sisters in real life.
The doublemint twins?
You’re half right…
No, don’t think so. Just gal-pals.
Mary Anne and Ann Marie