Your best bet to attain Air Mastery tattoos and be a viable part of this roleplay is to be a former master that strayed from the path of enlightenment, and here's why:

There is a select group of people whom attain the tattoos, and they are very few in number as well as very powerful in terms of raw skill. They are masters. They preserved an art that only a few thousand still know. They give up their life, a lot of the times sacrificing romances and personal tethers, to achieve that level of mastery. Now, I'm not saying that an Air Master couldn't have a significant other or anything, but I'm saying they would likely be less inclined to. They would be less inclined to care about of a lot of Earthly things.

So, if the entire point of this roleplay is focusing on bringing DOWN the Phoenix Kingdom that right now is doing a lot of good things for the Air Nomads, the Air Bending Masters aren't going to feel real obligated to help out the cause. Your best bet would be to be something like a disgruntled 38 year old Airbending Master that has become fed up with the bastardization of the Airbenders in the Fire Nation and the Phoenix Kingdom that is diluting culture and spiritual value. That, you can do.

What you cannot do is fit the Air Master archetype into a rebel because it doesn't make a lot of sense.