Are there any compliance concerns with scheduling the 1st payment 90 days out on a home secured by 1-4 family residential real estate?

Escrow if it is a 1st lien HPML. Could not get the origination system to produce correct documents nor the servicing system to handle correctly.

Could this also cause a negative amortization situation during the first few months?

That was the only thing I could think of was negative amortization. So that would require notation on the GFE that the balance could rise... but I couldn't really think of anything else.

Check your state law. There may be issues with some states.

If sufficient long-odd-day interest is collected at settlement or the first payment is increased, there won't be neg am.

Investor requirements may be an issue if the loan will be sold.