My initial comments are focused on the few months of this system, few months of that system, and a few months of some other system.
In my opinion, a good system has a specific foundation and methodology upon which the techniques are built. If the foundation is not properly understood, then the techniques may not function well. If techniques are worked from a foundation from a different system, kind of a mix-and-match, the techniques may or may not work well. It depends.
In my opinion, a few months is not enough time to properly understand how the foundation really works, nor to have developed any real skill in using that foundation to execute the techniques.
So when someone has spent a few months each in several different systems, I suspect they have not yet understood any of the foundations well, and while they may have collected some techniques from each system, they don’t really understand the engine that should lie underneath them and give them real authority and effect.
I guess I don’t really see those few months spent in several methods as being cumulative. Rather, they are incomplete starts.
Now, seven years in aikido, dan grade or lack thereof not withstanding, is significant. This assumes the training has been regular and reasonably intense, and not just dabbling now and again, over the course of seven years.
Instructor grading in a military combative method is a form of instructor “credential”. I don’t know enough about the military methods to comment further than that.
From the standpoint of presenting yourself to prospective students, your instructor credential and your depth in aikido give you what I would characterize as a reasonable credibility.
The other methods in which you have only a few months give you some level of perspective, but I would not play that up too much. That is my opinion.
Overall, I am in no position to judge whether or not you would be a capable teacher. I don’t know you. Maybe you would, maybe you would not. But you have some things in your training history that I feel are credible.
This is my opinion.
Edit to add: the two years each in Hakkoryu and Brazilian jiu-jitsu, and the two years between two different Karate methods may be enough to have some level of legitimate significance. These things add to your credibility.