Laminate does have a different sound when you walk on it, however, there are acoustical underlayments available that deaden the echo and make it sound much more like a real hardwood floor. Make sure to voice your concern so the appropriate underlayment is used in the installation process.
Carpet and padding are petroleum based products and therefore increase in price as the cost of oil increases.
Yes, engineered hardwood can be installed directly over concrete if it is above grade. There is even a system available to install solid hardwood directly over concrete floors.