They have a history of doing some odd things. For about three seasons before the Texans were added in 2002 the NFL had 31 teams and made it work. I think it was 5-5-5 in the NFC and 5-6-5 in the AFC with the extra team in the central. So they *could* do the same thing again, add one or two additional teams and just stick an extra team in one division. It wouldn't be fair to the teams in the division with the extra team, but they don't care as money is money and that's the important thing.
Ideally the re-alignment would be best if they added 4 teams and went to 36 where they could have 18 in each conference and go to 3 divisions of 6 teams each. I just don't think they could add 4 teams at one time, so maybe they'll go 2 in one batch in the next expansion and then 2 more five to ten years later.