Is this ok?
"Restrooms are on each floor except the 3rd floor; note that the 7th floor has only men's room, the 6th floor has only lady's room."--Orignal
Except for the 3rd floor, restrooms exist on each floor; however, note that the 6th floor only has a women's restroom, and the 7th floor only has a men's restroom.--Using a conjunctive adverb
Except for the 3rd floor, restrooms exist on each floor, but note that the 6th floor only has a women's restroom, and the 7th floor only has a men's restroom.--Using one of the FANBOYS
As originally written, your post is proper grammatically. To my ears though, I feel that it would be better to rearrange the word order, as well as to have an article (“a” or “the”) before “women’s/men’s restroom.”
We use a semicolon [;] to link two independent clauses, especially when the second one explains or adds information to the other. We can also link them together, as I have done, using a conjunctive adverb (moreover, nevertheless, otherwise, however, etc.) Finally, this sentence could just as easily have been written, again, as I have done, using “but,” or another of the FANBOYS after a comma [,].
The words, “note that” are emphasizing that the following information is different from, or modifies the information given in the earlier clause.
The word, “has” is just showing possession, as each floor has its own restroom. For example, “He has no money for lunch. She has no time to study. The car has no gas in it.”
My sincerest apologies if I have misunderstood. I hope that this helps you, Jonathan.