I haven't tried combining apples with other fruits when making the pie, but I think pears would blend well because they more or less have the same texture. With quince, what's typical here is a sweet jelly paste but solid in form called ''Membrillo'' (same name as the fruit).
I don't know if quince can be combined with apples and pears, as this way of doing it needs a lot of boiling time to turn it into mush practically.
