Having just come through this confusing process myself, maybe i can further clarify...
First,
the anesthesia spot is your priority, so apply broadly to those-- osteo, allo, whatever you want. Some of the allo programs/slots are categorical, meaning that they include 3 yrs CA training + a PGY-1 yr. Some of the allo programs/slots are advanced, meaning they only include the 3 yrs of anesthesia training.
Then go from there. If you apply to some advanced programs, then you will need to apply for first year spots. Keep in mind that if you match into anything in the DO match, it will automatically withdraw you from conflicting allo spots (e.g. you match into a DO internship, you would be withdrawn from all categorical allo spots). While I agree that doing an AOA internship is not really important, if you know you want to practice in one of the big 5, you need to think about this a little more. The statistic mentioned is probably true, but a little misleading. In order to be approved, your internship has to meet the AOA requirements for curriculum, including at least one month of FM. I think that it's likely that people who won't meet these requirements and don't care about the AOA approval just don't apply. If your program's curriculum doesn't fit the bill or offer you enough electives to make up the difference, you could be out of luck.
The way that I tackled this was to apply to mostly categorical allo anes. spots with a few osteo and advanced allo spots. Ultimately, I only interviewed at allo programs. I generally ranked the categorical slots higher than the advanced (because I really only wanted to move/adjust to a new hospital, etc. once), with the plan to scramble into a first year slot (probably osteo) if I had to. I contacted several places with osteo internships to lay some groundwork for this, but fortunately didn't need to worry about it. My program's base year base year meets the AOA requirements, with the exception of FM, which I will probably complete in my one month of elective time.
I can only imagine how complicated this could get trying to couples match, but people do every year. PM me if you have other questions, and good luck


