Is "ale" similar to German "sondern" (but … instead) ?
Not necessarily. It can be translated as 'aber' as well. Probably not in this case though.
Can it also mean " does not like?"
does not like is "nemá rád/ráda/rádo"
Why cannot the translation be "Kateřina does not have apples, but pears."?
The accusative plural form is "hrušky"
Struggling with this one. I understood nema as "does not have ", but not "does not have a". Can I have clarification on this please
They don't use 'a chair' 'a pear', but when converting to English we have to stick'a' or 'an'.. if anything it hits home how clumsy English is lol