Business plan etc. to get a merchant card ! Sounds rediculous, never had anyone been asked for that.
As to rates have seen as low as 1.25% and up to & over 2% . It all depends on the expected volume. The higher the volume the lower the rate one can argue for. ( & there is a bit of arguing so I'd get them to shop around on the merchant cards ) . Businesses that might have more credit card sales could expect lower rates.