You have put yourself in a tough spot because school districts have been going after people for lying about their residence. You have some criminal exposure for lying on the guardianship paperwork. I suggest you retain an attorney who deals with education issues. I can refer you to a few if you'd like.
I am a former federal and State prosecutor and now handle criminal defense and personal injury/civil rights cases. Feel free to check out my web site and contact me at (212) 385-8015 or via email at Eric@RothsteinLawNY.com. The above answer is for informational purposes only and not meant as legal advice.
Depending on the dates between these two documents don't people move? I have to assume that the child does not actually reside in the district where you seek to enroll him. If he lives there the prior statements should not be controlling.
Disclaimer: This answer does not constitute legal advice. I am admitted in the States of New York, New Jersey and Massachusetts only and make no attempt to opine on matters of law that are not relevant to those three States. This advice is based on general principles of law that may or may not relate to your specific situation. Facts and laws change and these possible changes will affect the advice provided here. Consult an attorney in your locale before you act on any of this advice. You should not rely on this advice alone and nothing in these communications creates an attorney client relationship.