Woah! That's a lot of parts changing there! Stop throwing parts at it and do some diagnostics please.
You obviously had a misfire if the CEL is flashing. Driving it like this for prolonged periods will destroy your catalytic converters. But the cats themselves are the result of the misfire, not the underlying problem.
Hook up a scanner that has live data and misfire counts to see which cylinder is misfiring, then go from there.
It could be a wiring issue (injector or coil circuit), compression (burnt valve, broken piston ring land, etc) or even a vacuum leak. But you need to have an idea which is the cylinder that causing the issue.
If this is beyond your capabilities, there's absolutely nothing wrong with taking the vehicle to a mechanic. Ask for a "diagnostics only" price. Then you can negotiate or consider if you want to do the repair or just pay for it...
Good luck.
