YOU SAID:

My dog and my sister alike will show up at the party should it not rain.

INTO JAPANESE

雨が降らなければ、私の犬も妹もパーティーに現れるだろう。

BACK INTO ENGLISH

If it doesn't rain, my dog and sister will show up at the party.

INTO JAPANESE

雨が降らなければ、私の犬と妹がパーティーに現れるだろう。

BACK INTO ENGLISH

If it doesn't rain, my dog and sister will show up at the party.