if i activate a unit and attempt to move them within 12 inches of an opponents unit and he chooses to react he could move or attack correct, if he chooses to

attack i do not get to attack back correct? if i activate a unit and declare an attack on a unit he can react and attack back but this situation we would both attack at same time correct?

when 2 units are attacking each other via the react rule both units would receive supression markers correct, would the supression markers go into effect immediately when resolving armor saves for the attack that put the supression markers on them, or any attacks after that is when the markers take effect?

and last one, if i have a unit with cc weapons and attempt to move in on a unit, ( say im like 9 inches away) if the unit chose to stay and fight the could only react with cc weapons or could they shoot zombies before they got there? thanks for answers

First 2 you are correct.

3rd you wouldn't get suppression save unless you reacted outside 12" by, "going to ground."

Last question is you may either,

1. Wait until they CC you to react, and only be able to CC back, or
2. Shoot the undead in the face with your ranged weapons at the end if their move before they get the chance to CC you. (Better option in most cases, and It will teach their player to suppress their CC targets before closing with them).

thanks

………Shoot the undead in the face with your ranged weapons at the end if their move before they get the chance to CC you. (Better option in most cases, and It will teach their player to suppress their CC targets before closing with them).

And this is what most people tend to not understand about CC in this game. It requires Long range support (IE snipers and/or Walkers)