I'm still knew with families so I may not be the best help.
Ummm... are the enemies sprites all one object? or are they multiple different objects? Typically you can make one object many different "animations" and then choose(animationname1,animationname2) based on the variables you have set up.
The array would be set up like so Z=0
X or Width = Number of monsters - 1 (0 based I think, so 0 would be your monster)
Height or Y = 1, The variables you want to store for each monster.
Then at the beginning of the game you would feed in the info
X at 0 would be monster 1
Y at 0,0 would be initial round for monster 1
Y at 0,1 would be frequency for monster 1
X at 1 would be monster 2
Y at 1,0 would be initial round for monster 2
Y at 1,1 would be frequency for monster 2
etc....
IDK I'd look into arrays if I got a chance, they are real simple once you get the hang of them