Wow - that's a lot of questions.
I'm not sure what end goal you are after. Many folks abandon the Mitsubishi filters for other aftermarket brands. Do you want to use only genuine Mitsubishi parts?
I wouldn't seek out one of the Mitsubishi filters, for a couple reasons. Not having a anti-drainback valve is unusual (these days) and I'm pretty sure one can get improved filtration specs with a similarly priced aftermarket replacement.
That being said - why worry about the confusing Mitsubishi oil filters?
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View my fuel log 2015 Mirage ES 1.2 manual: 49.6 mpg (US) ... 21.1 km/L ... 4.7 L/100 km ... 59.5 mpg (Imp)