the iranians can open as many oil bourses as they wish but they will never fly too high, oil will always be traded in civilized places like chicago or london or perhaps even dubai. oil producing countries, including iran, care too much about their biggest moneymakers to bet them on politically unstable locations unnecesarily. as to your other points:
1. the end of the us dollar hegemony began about a decade ago. it is true and it is not a bad thing. the segniorage privileges the us had because of the position of the dollar in international foreign exchange markets allowed external and monetary imbalances to grow to bubble proportions in the us.

2. you are absolutely right, the prices of oil and the us dollar are correlated. since oil is quoted in us dollars, a decline in the value of the dollar requires an increase in the price of oil just to keep it constant against a basket of world currencies, and that is part (but far from all) of the reason why oil prices are going through the roof

3 and 4. since prices of oil and food have raised so much already, they are unlikely to grow at the same pace in the near future because they start from a much higher base. and yes, those prices will pass through wider inflation indeces, but the lower price of housing will in turn have a deflationary effect. i haven't taken a look at the fed's inflation models and all the current data they are feeding into it, but a recessionary (or at least slowing) economy suggests there are no endogenous (and therefore self-reinforcing) inflationary pressures, but only external inflationary shocks that are, by definition, temporary