The clerk is responsible for making sure all docket entries are correct, that all exhibits have been filed, all relevant documents and papers are ready, and the clerk determines that all required fees have been paid. The clerk will notify you of any defects in your filing. So everything you need to have filed, if you have not received any notice from the clerk, you have apparently filed. What is contained in your brief, however, is not reviewed by the clerk, so you may not receive any notice of defect if your brief is missing information or does not conform to court rules.
A respondent may make a motion to dismiss a leave to appeal based on the ground that an appeal is not within the jurisdiction of the court, which one of your defendants has apparently done. You should still have time to correct this defect in your brief, should it be necessary. Because the Supreme Court does have jurisdiction, however, I really do not know if this motion to dismiss based on these grounds will fly, whether you stated the basis of jurisdiction or not. I have seen briefs submitted that do not contain this.
Under Rule 7.301(A), Jurisdiction, 7.301 (A)(2) says that the Supreme Court has jurisdiction on a review by appeal any case pending in the Court of Appeals or after a decision has been made by the Court of Appeals (see MCR 7.302).
What you could do is send in an addendum to your original brief, titled Statement of the Basis of Jurisdiction and write that "Jurisdiction was conferred on the Michigan Supreme Court by Michigan Court Rule 7.301 (A)(2)." You can add further details stating that the judgment sought to be reviewed and appealed by the Court is from a decision made by the Michigan Court of Appeals which was entered on such and such a date, and that your leave to appeal was filed on such and such a date, etc.
You can check with the clerk of the Court to see if you even need to add this, or what the best way to add it is, should it be necessary. You usually have time to correct any defects in your filing papers and documents - I am not so sure you can correct defects in your brief, but I imagine you can.