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You pose a very interesting question. In the strictest sense of the definition you did own (even if only 25%) your main home for a period within the three years prior to purchasing your new main home.
Here is a link to IRS Form 5405 which has the instructions:
You will note that in the section "Who Can Claim The Credit" it is:
"You (and your spouse if married) did not own any other main home during the 3-year period ending on the date of purchase."
They are not clear about what constitutes ownership, however I would err on the side of caution and say you might not be eligible for the credit. Not only did you have ownership but you also moved in and it became your main home for nearly 8 months.
If you take the credit, and you get audited you would have to make the case that it was not your main home. There is no precedent for your issue as this is new ground for everyone. There is no way I can be sure what the IRS would do in an audit scenario.
I realize that my answer is not definitive but, under the circumstances I have no precedent to draw upon.