Mid-Long Term Investing for Private HS

[bns3092]

I'm curious what y'all recommend for short-longer term investing for private high school? My wife and I have four boys ages 12, 10, 6 and 1. They currently go to a small and fairly cheap catholic grade school which we love and has us wanting to send them to a catholic high school nearby. The tuition for the high school is also relatively cheap(around 7k/year right now). We have 20K in I bonds that is earmarked for their education fund. I usually get a work bonus of around 20k/year that we'd also invest in the future. Our timeline is anywhere from 2-3 years for the oldest to 13 years for the youngest. I didn't really want to get too in-depth with our finances just wanting more generic answers to the questions below.
-What type of account is best in terms of liquidity and tax treatment? 529, brokerage, more bonds, high yield savings
-What type of investments are the best mix of risk without really risking the principle? Percentage of Stock/Bond mix?
-Anything else I'm missing?

Thanks for all of your help in adavance!

[Gin1984]

Does your state have a tax deduction?  Does it allow you to pull for K-12?

[reeshau]

Does your state have a tax deduction?  Does it allow you to pull for K-12?

An additional 529 question: does your state negate tax benefits if you deposit and withdraw in the same year?

Regardless of account, you should not invest in stocks if you plan to use the money within 5 years.  Your I bonds sound like a good basis for your 12 year old.  Then you could look at a 529 for the younger ones, subject to these questions.

[bns3092]

$20,000 tax deduction for married couples. You can pull for K-12. I can't seem to find whether the tax benefits are negated for money withdrawn in the same year.

[reeshau]

I can't seem to find whether the tax benefits are negated for money withdrawn in the same year.

You'll just have to dig for it.  Here is the wording from the FAQ for Michigan's plan.  (bold added)

Q:  Is there a Michigan income tax deduction?

Michigan taxpayers may also be eligible for a Michigan income tax deduction on contributions made to MESP up to $10,000 for married couples filing jointly or $5,000 for individuals filing single per year. A Michigan taxpayer is permitted a deduction from Michigan adjusted gross income for a contribution to an account less any Qualified Withdrawals made during the tax year. Amounts transferred from another 529 college savings plan are not eligible for the Michigan income tax deduction.

You should talk to a qualified tax advisor about how Michigan tax provisions affect your circumstances.