I don't understand why not. What lodging information are you referring to?

Nationality?

Most airlines (mine included) require a signed parent/guardian consent form for under 16s travelling unaccompanied.

You've been in thailand 8 months and out 4 months during the last year? Might possibly raise an eyebrow at immigration. I'm not the expert, but it begins to sound like you're not a tourist.

It's worth remembering that you don't need a "return" ticket back home ... you need an "onward" ticket. Think in terms of the cheapest flight to a neighbouring country that you can cancel or just lose at small cost.

The "which airline?" part of your question doesn't lie in the remit of this group.

If you're going to volunteer, you'll need a work permit of some sort.

I'm sure that our resident experts will fill you in with visa options shortly.

You won't get a "visa on arrival", you'll get a "visa exempt" entry which you can (for a fee) extend for another 30 days.

Thai immigration will know that you can extend. Be sure to also have your hotel booking and 20,000 baht (or equivalent) in CASH.

The issue will be with your airline accepting you for travel with a return ticket outside the 30 day window. Check with them that they're aware that extensions are commonplace.

The experts will correct me if I'm wrong, but I think these sums of money apply within Thailand when you ask for an extension of stay, rather than the initial application in your homeland.

5 or 6 times a year? I think you'll start getting serious questions asked at immigration soon. I'd look into METV. There are experts here who'll give you more accurate options shortly I'm sure.

My instinct is to say "in no way".