flapper

All the videos make swapping a flapper seem super easy, except that my old flapper won't come off. The holes are too small and not flexible enough to get them over the wings of the flapper holder. It appears the only way to get it off is to cut it. Is that ok to do? If so, what's the best way to...

I have a Fluidmaster 400 series toilet fixture. It's leaking. You'll see these things in the attached pictures. I got a flapper from the hardware store but it doesn't seem to be long enough. What kind of flapper do I need? Is there something else I have to do?

One mounting ear snapped off the overflow tube, now the flapper is all lopsided and needs to manually centered after flushing. Should I snap off the other ear and get a flapper that just mounts over the tube? The tube doesn’t look replaceable. Looks like it’s part of the whole tank...

My old flapper was leaking as I flushed, so I got it replaced. I've put a new flapper on the toilet (a Toto 3-inch), but occasionally when I flush it still won't form a tight seal so it'll leak. If I flush it again it usually fixes itself and seals properly. This only happens 30% of the time so...