Under LOI - Looking to raise capital

I'm looking to see if there are investors that would provide capital in a structure that's a hybrid of Mezz debt and a traditional search deal.

Deal Info:
$3m in Revenue
$670k SDE
$2.75m Purchase price

The seller is willing to finance 65% of the deal and I have $500k of my own capital to finance. Looking for a partner for the next $500k. A possible debt structure I'm considering below, but would love feedback.

-$500k investment
-Interest only note at 9% for 4 years, ballon payment at end of year 4 (this can easily be repaid by refinancing the business)
-First 2 years standby but accruing
-Would come with 7.5% equity stake in the company which the investor could opt to be bought out of at year end of year 4.

At a 5% growth rate for the business value this would be 18.8% rate of return and a MOIC of 2.0 for the investor (no growth and it's 16.2% and a MOIC of 1.8).