It's perfectly fine within the Bitcoin protocol to create, sign and broadcast a new transaction, using output from an earlier transaction that was just pushed before, and has not been confirmed yet.
Interesting in theory, but try DOING that with an actual Bitcoin client. I've yet to see one that will let you spend Bitcoin from unconfirmed transactions, and IME they generally require multiple confirmations before they allow you to then move that Bitcoin on down the line.
It's a GOOD thing actually, as a security measure.
And "commonly an hour or two" is even more bollocks.
Nope, it's experience. I do grant that it's less likely to take that long on Lightcoin.
And yes, obviously, there is no such thing as chargebacks with cryptocoins. I mean the concept of a transaction becoming irreversible, or permanent, or set in stone. With Bitcoin, theoretically, a transaction is not 'guaranteed' (although *extremely* unlikely to be nullified) until it's confirmed. With paypal or credit card it can be reversed (and happens quite often) until the chargeback/dispute period expires, and that's typically 3-6 months.
Which is different from a chargeback. On a chargeback, the transaction WAS confirmed, then later the CC issuer was told to reverse it due to some reason - non-delivery of goods or fraud being probably the most common issues leading to a chargeback.