Some easy questions, some harder ones too!

[JohnT]

Does a "solar blanket" add a noticeable amount of heat to an ig pool? I'm thinking, when it's hot, we'll be IN the pool and really not using the blanket much during peak hours. Is it still effective?

A solar blanket doesn't add heat. It holds in heat that you already have. Real benefit is overnight or cool, cloudy days. With a heater you won't be paying to reheat the water, and without a heater you save some of yesterday's solar gain.

If I want to hook up a pool heater, do I have to do it during the remodel, or can it easily be added afterwards?

Other than running gas or power, it isn't hard to add after construction. If you do just a little planning on your plumbing, it can be trivial to add.

And the hard ones:

Is 1 HP pump enough for this size pool?

I have a slightly larger pool and a 1HP is fine. Water features etc. might make a difference. Make sure your filter and plumbing can handle the flow of the 1HP pump.