When or if I hit the green on par 4 on my first stroke, does that count as fairway hit aswell or do I simply just remove that hole from my stat card (regarding fairwayhits)?
Statistics are not always based on the rules of the game, so any answer you get really depends on the interpretation of the individual keeping the statistic or the system used to measure the statistic.
The PGA Tour counts hitting the green from your tee-shot as a Fairway hit. Reference the bottom of the table on the below link you will see:
The percentage of time a shot comes to rest on the fairway or the green.
However, the Chart Golf Stats website claims it counts as a 'no-score':
Note: on par 3 holes, where you are meant to hit the green with your tee shot, you do not record fairways hit, instead recording no-score.
Similarly, My Scorecard also states that hitting the green from the tee does not count as a fairway hit...
This statistic refers to the number of times during the round your drive landed in the fairway (the fairway, not the light rough). It is similar to the greens in regulation, except that the maximum number per round is less than 18. This is due to the fact that you are supposed to drive the green on a par 3, and as a result we don't count those holes for the fairways statistic.
EDIT: My interpretation of the statistic sites is that, on a Par 4, hitting the green WILL count, while on a Par 3 it won't count. However, the statistic is not relevant on a Par 3 as you are not intended to hit the fairway at all, therefore hitting the fairway on a Par 3 is actually a bad thing and should be considered a negative statistic.
In short, hitting the green on a Par 4 should count as a fairway hit and a green in regulation.
My advice is to follow the local rules. If your golf club has a statistic system they follow then ask them, if they don't then choose a system and follow their rules.