I have replaced a bad rod bearing before but not on a Fiero. If the business end of the rod is egg-shaped from knocking, all bets are off, "Sort-of".
You may want to check for journal scoring. If scored all bets are off again, "Sort-of".
I once found myself in a pinch such as yours and an old -schooler told me about a trick fix. Find a worn out leather belt and soak it in some oil. Cut a length of belt equal to the circumference of a rod bearing. Poke oiler holes in the appropriate places and put the leather bearing in place.
When you fire it up the expression on your face will be priceless!
No,,,,,,,,,,,, I wouldn't advise replacing the remaining 5.
"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut