Being swayed by heresy…

I'm considering starting a 2,000-point army for Chaos, and the Alpha Legion is the most intriguing option for me. I want to build a solid list using the Deceptor detachment, but I'm unsure where to begin. I apologize if this is a bit unclear, but I aim to use as many loyalist models as possible to capture the essence of the Alpha Legion appearing unexpectedly. The paint scheme featuring active camo transitioning from loyalist to Alpha Legion has really inspired me.

What would be acceptable loyalist proxies for Chaos Cultists and Legionnaires to take advantage of the infiltration rule with the detachment? Also, how many proxies would be considered too many?