1, 2 and 3 do. I studied Russian for 2 years at university. Russian and Latin grammar are very similar. The exceptions would be the verbs. Russian has way fewer tenses, but it uses so many prefixes. http://dcc.dickinson.edu/grammar/latin/declension-cardinals-and-ordinals
A singular cookie is a crustulum: since it's a neuter noun, we use crustulum (same form) both for subject (Crustulum mihi placet--The cookie pleases me/I like the cookie, where crustulum is a nominative singular) and for direct object (Puer crustulum vult--The boy wants a cookie, where crustulum is accusative singular). As a neuter noun, crustulum uses the ending -a (crustula) when plural, for both subject & direct object: Crustula mihi placent; Puer crustula vult.
I hope that helps.