No it's not simply legitimate self-defence, the Pasdaran murders of intellectuals outside Iran began before Saddam invaded. Efforts were made to extend Shiite Islamist influence ideology and arms into Bahrain, into Lebanon, into Iraq, into Qatar, into Kuwait - probably elsewhere as well. The Iraq invasion and self-defence is only aspect of its behaviour in the 1980s.
In which case you can do the courtesy of accepting that Iran's behaviour is part of an opposite pole of imperialism, instead of charging in aimlessly. Iran doesn't stand up against the oppression of Muslim Chechens or Uighurs - because it is in tacit alliance with Russia and China which are both as we would presumably both agree imperialist (assuming your rough definition below).
Iran has attempted to threaten and coerce peoples outside its borders so this definition doesn't prove anything about Iran.
Did my list include food plants? It's an irrelevant inclusion here.
Exactly what it's done in Iranian Kurdistan certainly since the end of the conflict with Iraq. Virtually all Iranian Kurds will describe a scenario of intensified imperialism and centralisation comparing the Shah with Khomeini. (Not to say the Shah wasn't a dictator). It was Iran that tried to destroy the Kurdish movement in Iran, to length of a trio of assassins executing Dr. Hassemlou in exile in Europe at point blank range. It has plundered Kurdish territories to new depths. It has stepped up hot pursuit into the Kurdish regions of Iraq in its fight against PJAK.
What are the relationships between Iranian firms in Lebanon other than ones of domination and plunder? Likewise, it has constantly sought to wrest control of islands in the Gulf that are not its own by any stretch of international law, purely for gas exploration purposes. It has heavily threatened not just Israel but Jewish groups outside the country, as an offshoot of its ideology spilling beyond its borders.
It has constantly shown this inclination. It's how it has tried to offset its vulnerabilities (economic and ideological ones) as a dictatorial anti-democratic regime.