1. Deploy 5 zombies. 2. Kill something. 3. A summoned zombie will have Latch On and Death Nova: Disease Rank 3 as upgrades. 4. This is incorrect as the description of S:FC claims that a zombie WITHOUT upgrades is supposed to be summoned. Proof: @Sokolov
Zombie Plague has the same issue, although it doesn't state whether it summons a festering corpse with or without upgrades. Clarification on that one would be welcome.