Yes - all are familiar in the UK. Walk into any distributor of any product that comes in different models and sizes and ask for a brochure: cars, TVs, washing machines, amplifiers........
Cruise lines send out brochures outlining the range of cruises offered for the coming year.
A leaflet would usually be a single piece of paper, and often handed out in the street, advertising some special deal. e.g. 2 pizzas for the price of 1; 10% off today only at some shop or store.
Pamphlets, for example, are displayed in racks in a medical centre. They are either a folded sheet, or two folded sheets stapled together, giving specific information about conditions, or warning signs of conditions. That is, pamphets provide information about a specific subject.
I agree that a "leaflet" usually refers to a single sheet, whether printed on one or both sides. But a "pamphlet" doesn't have to be limited to two sheets, even if folded to make a total of eight pages. A pamphlet doesn't have a hard cover, and at some point it becomes a paperback book, but I don't think there's a hard line between pamphlet and paperback book.