If the cycle is complete and you were able to track the relevant parameters rise and fall, then adding in a small amount of livestock at a time like that shouldn't cause any spikes. That might be a slight rise, but if you tank is cycled, the live rock and filter media should handle it just fine.
How were you cycling the tank and how long it take to complete?
55g FW South American community tank
20g SW FOWLR tank
2.6g Fluval Spec III SW reef