extending air pipe won't work, the length of pipe supplied with those types of flush mechanisms are usually already the max length they can be - any longer and they don't function properly. better off with one of the other two options.
In my experience it's the toilet bowl which is the limiting factor. We had a high level cistern which worked fine until the toilet needed replace. After that water splashed everywhere. We had space so lowered the cistern, however you may be able to restict the flow by putting it through a constriction in the pipe or round some extra bends.
Have you thought about putting the flush button on the ceiling? You could also try replacing the flush button that comes with it with one which allows more compression.
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