In your example with ου σκύλους αυτός I believe we may retain the article even in my dialect
. Not always though; you could omit the article. Actually we'd probably say "αυτός ου σκύλους".
As for the article paradigm:
Nom ου η του
Gen (τ') (τ'ς) -
Acc του(ν) τ'/'ν του
The genitive articles are in parentheses because in northern dialects the genitive is eradicated. We only use it with proper names; never with common names. For common names we use από + acc. Ηence I did not give a neuter article at all.
In the accusative the fem. article is τ' before fricatives and liquids and 'ν before stops and vowels:
'ν κουπέλα (pronounced [ŋgupela])