In 1 you're mixing up dialects (and their respective grammars): leis an bhfear, leis an bhean. You should either have "leis an bhfear" and "leis an mbean" OR "leis an fhear" and "leis an bhean".
In 1c you should have "lena ndúirt sé é", since it is an indirect relative. You could alternatively say "a ndúirt sé léi é".
Also you English translation for 1c sounds a bit strange. I know it's a literal translation, but "to say something with someone" it doesn't really make much sense in English: better to use "to" instead of "with".
2a: Bhuail mé LEIS an bhfear... (!)
3. THE students
Reading to the end, I see you picked up on most of those by yourself.
Bulaí fir!