I live in tehran and I contacted the local travel agency which is close to my house I asked these questions on the phone and here are the answers.:1-Can Foreign Tickets (i Mean Tehran Yerevan) be Issued with a Scan of the Passport (without having the Passport Present)? YES2-Is it possible to issue an E-ticket for the foreign trips (therefore you do not need to show up at your agency to pick up your tickets)?YES3-Is the price in the agency the same as what is indicated in MAHAN site? it can be 5% different and earlier you buy, lesser the price will be.4-Can you buy the tickets when you arrive to Tehran in a local agency for a trip 3 days later? At this time they are not so many travellers so they think yes it's possible.
but I think A visa is needed for Armenia,aint'I?