I assume the top picture is your current fireplace insert? Is it too late to re-frame the fireplace to be centered between the two windows/doors? The exhaust tube can be adjusted to accommodate the change. Our raised hearth starts about 2-3" below the insert of our wood burning fireplace.

When you have the wall opened up already, you should centre your FP. If you don't, it will bother you forever after. And check your local municipality for code requirements on hearth. My gas FP still needed 12", less than the required 16" for wood. And possibly think hard on a raised hearth in your location. They are a bit of trip hazard near traffic routes/doorways. Just use space already left in wood floor. A flat neutral material like slate to co-ordinate w/surround would look great.

You should have gotten an installation manual when you bought the fireplace. It will have all the information you need regarding clearances. Could you ask the retailer you bought the fireplace from to give you some help?