A bit of AA experience if its any help.
I think you are spot on with the first tradition. The guiding factor has to be the common welfare, so you are right to be a bit cautious.
Where someone is in their step work is also an important factor. 5th tradition I guess, what would someone talk about who hasn't done the steps. How will they help the group to carry its message to the person who still suffers if they have no experience of the message?
I come for a town where we took political correctness and non-judgmentalism to extremes. Call it apathy in disguise. We would never presume to judge whether a person was suitable for a speaking engagement, and it was taken as a given that all people in the fellowship, regardless of time, step work, or anything else, are equally capable of speaking and have a right to do so if they wish.
The result? AA is banned from all rehabs and detox's unless the institution itself selects a speaker. We sure failed at Trad 5. I really began to see what that actually costs when I went to other centres where we have pretty free access to other A&D services.
Well done on your responsible attitude.