hi faridzad, don't worry, yeah all these factors u listed might make the process longer; but at the end it's still case by case; as Arezoo said, this world today is so virtual and without borders that it's so normal for a couple to be of different nationalities; many couples met online, as long as they can see u r genuine from other proofs than it does not matter; also, anyone correct me if i'm wrong but if u marry a foreigner u don't have to register the marriage in Iran or Syria or whatever; u can register it only in Canada for example right? if u would register the marriage in Iran, then the children will have by default Iranian nationality, right? (which especially for boys should be avoided - after that they will b called for military service in a country they have never lived in, right?)...what i try to say is that they cannot expect from everyone to have that marriage registered in Iran for example, if it's possible not to...yeah they could ask u why u didn't but it's kind of obvious ??? also, i don't know if in that document u can add people who r foreigners....
anyway from my humble judgement ur main focus now should b getting those notes to see when ur interview will b and also the reason (security - prepare urself with details abt ur military service, maybe ur travels) or abt ur relationship (get ready for any possible questions abt her, u as a couple etc)...also, in case it's about the relationship have already extra proofs handy (her visits, communication proofs, etc)
also, what it's strange to me, if u r in queue for interview, shouldn't they sent u email/letter already abt the interview date ??? who knows why they didn't yet (maybe the situation in Syria is a reason)
good luck!!
