Phew, this thing was a lot more work than I thought!

Points:

delidog:
23 E's = 46 points.
5 I's = 10 points.
11 O's = 22 points.
7 S's = 8 points.
Total points = 88.

Casper & Kitty:
13 A's = 26 points.
2 U's = 4 points.
5 C's = 5 points.
0 K's = 0 points.
Total points = 35.

Puzzle:

O--- a--e- --e -as- --ee -as -ee- cu- -o--, o--- a--e- --e -as- -i-e- -as -e- -oiso-e-, o--- a--e- --e -as- -is- -as -ee- cau---, o--- --e- -i-- -ou -i-- --a- -o-e- ca--o- -e ea-e-. ~ C-ee --o--ec-

Available letters:

BDFGHJLMNPQRTVWXYZ