Off the top of my head, the first two look like they are from season one, given the quality.
Now for a little Ranma history. The series firs hit Japanese airwaves in April of '89, and featured high-quality artwork and a storyline that followed Takahashi's original rather faithfully. However, it did not get the ratings expected, and so the entire series almost stopped off at a mere 18 episodes. It was taken off Japanese air for a while and returned at the end of the year with a slightly altered look and some reordering of episodes (hence the earlier appearance of Shampoo--she was a fan favorite in the manga and so was brought in quickly to boost ratings). Technically, the new season was an entirely different series, and the production staff began numbering the episodes at 1 rather than 19. The show was released outside of Japan as one series, so the episode numbering is a little off.
Now, all that does have something to do with what I'm about to tell you--I promise!!! I know where
this cel is from, but it's difficult to know how you want to number it. Technically, the first season is called Ranma 1/2, and the subsequent seasons are called Ranma 1/2 Nettohen. So, you can do it one of three ways.
Ranma 1/2 Nettohen Episode 73: "Ryouga's Proposal"
Ranma 1/2 Episode Episode 91: "Ryouga's Proposal" (this would consider both series as a whole)
or
Ranma 1/2 Season 5 Episode 3: "Ryouga's Proposal"
| It's from the episode where Ryouga stubbles upon the Ghost Cat (bakeneko) and it possesses him and proposes to Akane. |
I'll take a look at the others this weekend. Given the shape of his nose in the second and his face in the first, I think they're season 1. It'd be easier to tell with the first if his hand wasn't in the way.
I've only watched the movies, the
But I did get the others. 
GO, KLET! GO, KLET! 
Where have you been!?!?!?
