300k Maintenance, and OEM Parts order

I am basically looking into performing some maintenance tasks on my '03 Celica GT-S as I am now over 300,000 Mile mark. As the tasks I'm looking to perform are going to be done in 2 phases I wanted to run them by some other people who are more experienced in working on cars than myself and ensure I am ordering the correct parts for the job.

1st Phase
Flushing out the Coolant System & Changing the Transmission Fluid, I have Toyota's & A Forum guide on how to do this, though I have done this before I intend to use the Toyota Genuine Coolant (Pink) will need something like 6.7 Quarts? And 3 quarts of Red Line MT90.

I will also be changing the Fuel Filter (for the 1st time) but was also curious being so cheap would it not hurt to change the Fuel Pump Filter Screen too? These are the parts I am looking at here:

FILTER, FUEL PUMP 23217-23010
Fuel Filter 23300-23030

Will this be everything I need or is there something I'm overlooking?

2nd Phase
I will admit I have been terribly inconsistent with oil changes in the 10 years that I have owned this vehicle frown And as of recent I have discovered what "Sludge" is and what it does. The guy at Oil Can Henry's was not impressed to say the least. So I can see sludge build up under the oil cap, Pulled the PCV Valve and the hose was completely clogged (cleaned that out, replaced the PCV Valve) though my suspicions is there is probably allot more sludge.....

So onto my next point, I want to pull the valve cover off and manually clean that area with the camshafts, drop the oil pan clean that out with the strainer including the valve cover and replace the Oil Control Valve screens. I suspect those are clogged as I got a Check Engine light the only 2 times in the last few years I have pushed the car to 6,000 RPMS instead of the lift, I make it a rule to keep my car below 4000 RPMS to conserve the engine life. I intend to clean those parts out as thoroughly as possible then run 1000 Mile intervals with Marvel Mystery Oil replacing the Oil/Filter a few times in hopes of cleaning out what remaining sludge I can get too. My brother in law worked as a Mechanic for a few years and seems to feel confident with the process though suggesting it’s a time suck reluctantly is willing to assist me. I also intended to simply replace the gasket and lift bolts at the same time I do the work and here is the needed parts I came up with:

Valve Gasket 1121-388600
Lift Bolts 90105-06293
Genuine Toyota Fluid 00295-00103

My biggest question is will that Valve Gasket come with the 4 rings in the center where the coils sit? I also believe there is Silicone that is applied to 2 spots? What Silicone do I need for that? Is there anything else I might need to pick up in respects to OEM Parts to complete this task?

Thanks for your consideration.