Morning.
Been a while since I played Q37 so pulled the book out and had a quick add up.
There are 4 solo scenarios in the book, the first 2 have Zombies as foes, the last 2 have Bugs (from the description think of Alien).
Here a list, figure in () is the starting number, other is my best guess for what you might need dependent on how you roll for NPC reinforcements.
Plague Zombies - standard Zeds, no weapons (4) 10
Soldier Zombies - ex soldiers, still armed with carbines and a rudimentary ability to use them (2) 6
Bloater Zombies - full of gas and explosive (4) 6
Queen - (1) 1
Acid Spewer Bugs - have ranged attack (0) 4
Warrior Bugs - standard bug (4) 8-10
Royal Guard - as per standard but tougher and more dangerous (4) 6
You should be able to get away with less than the maximums so long as you're killing the foes regularly.
Apologies in advance if I've missed anything.