You may need to change the fuel filter again.
If it were my vehicle, I would try to drain as much gasoline out of the tank as possible and replace with a FULL tank of gasoline, which will greatly reduce the amount of possible contaminates in the fuel system.
To change the 3 rear plugs with as little disassembly as possible, drive the front wheels up on a ramp and get to the rear 3 plugs from under the vehicle....you can reach right up at get them from under the vehicle.
I remove only 1 plug at a time so as to avoid introducing any issue of plugging the wrong wire to the wrong plug.
If the vehicle is not wanting to start/run, a check of the fuel pressure at the fuel pressure test point, located at the center of the front fuel rail (line that connects to the 3 front fuel injectors) would be in order.
THIS will tell you if you are getting fuel to that point or not.
The test point looks like a tire air valve......
Of course, use care to avoid spraying fuel at that point.
I would also add a can of Berryman's B-12 Chemtool to a full tank of gasoline to further desolve any contaminates in the fuel system.
Check a new spark plug to see if they are crudding up again.
As mentioned, new motor oil to flush out any junk that got there.
Some have reported problems with the Multi-prong Bosch plugs, if they are working for you, then I would not worry, but just a note about a possible cause for misfires.
It may be more of an issue now, with junk in the fuel, but only an inspection can tell.