Using そうな grammar point in sentence as past negative
 

I wrote this sentence:
お兄さんが大嫌いそうな景色です。

The meaning I intend is "It is scenery that my brother hates."

I'd like to make it negative past tense.
This is what I think it would be:

お兄さんが嫌いじゃなさそうな景色でした。

Could someone confirm if that is right / grammatically correct?

The reason is, i'm confused a bit with the じゃな . My brain is programmed from earlier studies of Japanese to use じゃなかった to make it past tense with optionally using です。By default I wanted to write it as:

お兄さんが嫌いじゃなかったさそうな景色です。


As a broader comment, the examples online for this particular Japanese grammar point do not have many negative past tense sentences. Before posting this I've visit a number of web sites but couldn't find much help.

>お兄さんが嫌いじゃなさそうな景色でした。

It seems to be correct but not natural.

I would say "お兄さんが嫌わなさそうな景色でした。" or rather say nothing.

>お兄さんが嫌いじゃなかったさそうな景色です。

It has some grammatical problems. And I cannot imagine the situation. the brother have never seen the scenery, right? Then he never hated the scenery.

I would say "お兄さんが嫌わなさそうな景色だったよ。".