Regarding the Guards, they will only summon if an NPC or Player calls them in, so if the Zombies appear on the far, far left they will normally be unmolested. However on the right there's a Yellow npc that can see them and will pull the Guards in if a fight starts. After a while if the the guard doesn't see a Zombie it will leave the area and the spawn will return to normal. The trick then is to pull a zombie from the left across the Graveyard, so the Guards already there see it; the Zombies move faster than the guards, so take it out the Graveyard gate and over to the steps; let the Guards get out the gate, and close it behind you. The Guards that have spawned won't now see the Graveyard, the NPC can see the Guard there so more won't be called in, but if you then flag to the Zombies and pull them over to the far left so the first blows are out of the NPCs sight, he won't call more in against you for the new fights. It's tricky, but you can get a little bit of peace for yourself this way.