My Super 8 has an oil change interval of 1200 miles. My Aprilia Sport City 250 has a 6,000 mile interval. The difference is that the Aprilia specifies synthetic oil and has an oil filter. Although I use synthetic in my Super 8, with no oil filter the oil will get dirty and need replacement even if the oil itself is still good so I change it every 1200 miles. As for cleaning the strainer, I have yet to find anything in it and I have over 10,000 miles on my Super 8. I did install magnetic drain plugs. I did find a little fuzz on the engine drain plug the first few oil changes but it's been pretty clean since then.
The intervals for changing the final drive oil are probably excessive.
My super 8 didn't require a valve adjustment until 2500 miles. The newer ones require the first one much sooner. I'm not sure why that is. I have now done 5 valve clearance checks. They required adjustment 3 out of those 5 times so that interval is probably about right. On some of my other bikes I have found that the valves stay in spec much longer that the interval specified so I don't check them as often as the manual specifies. The results for your scooter may vary.
BTW, my Super 8 runs better now than when it had low miles on it.