Can't help directly with your question about boots but I do know a bit about plantar fasciitis. For those who don't know this is not a foot "condition", like a bunion or something. It's an injury. There are small tears in the tissue that makes up the sole of the foot. If you don't let it heal it will eventually give you heel spurs and may require surgery.

Keep in mind I'm not a doctor, just a fellow hiker. You may need professional advice.

You pain in the morning with the "first few steps" it typical. What happens is that at night the plantar fascia shortens a little. When you put weight on it it stretches and causes those tears to re-open. This keeps healing from happening. The solution is to get a special sock to wear at night that keeps your toe closer to your knee. Take a look at http://www.thesock.com/ for an example. This keeps the plantar fascia stretched while you sleep so every morning you don't have new tearing going on.

The other piece of advice is to never take that first step in bare feet. Put your shoes (with good orthotics if needed) on while you sit before you get up.

I also think you'd be better off in running shoes (perhaps with orthotics) than in boots. They are lighter to hike with and generally better for your feet.

Just my 2 cents.