Better apply for an E category Cambodian visa when entering the country. If you only get a tourist visa, just ONE extension is allowed, permitting a maximum of 2 months in the country. If you believe that's not enough time, go for the E visa, which can be extended for 3, 6 or 12 months.
Nonsense. This embassy is located in Europe, so they IF they choose to accept only EUR statements that's fine but they can't also accept USD statements. Also, Thailand uses the Baht, not USD.