Just talked to Footer Engineer

Why do a basement?  Nobody can give me a good reason.

Mainly because you'll be at least getting 'something' for the money that you are spending.  You also may have typically less piers with a basement.   However, there are other ways that you can reduce piers using a crawlspace - by using trusses and/or IJoist.  

Regarding Piers:

You need to try and get the piers in line - on the same soil - also, it's hard to keep footer line low because you can't get into the hole - so, you have to bring them up pretty high.  

What about 'sonotube'?

That's a good idea - have to sit the tubes on concrete (yes, you'll have to put a footer of concrete in the hole and you'll have to rebar (just put a matt and concrete over that matt) through.)   Yes, I'll need to see what you are sitting that sonotube on - you'll also have to reinforce it by drilling anchors or using epoxy or rebar (sic).  It's a little labor intensive to do this - so you'll need to weigh your materials cost vs. whatever.

So, what about the county inspector?

So, usually, as long as I (engineer) am involved, they are good with it.  I'll give you a letter on the foundation.  However, I always recommend that you TELL the county inspector what you are doing - to give him the option of coming out and looking at things.  Just, tell him that you're using me.