Hotaru does not get a henshin in the anime.
Hotaru Tomoe shows up in episode 112, in the Sailor Moon S season. In the subtitled version of Sailor Moon the episode is called "Who is the True Messiah? Chaos of Light and Darkness," and in the dub of Sailor Moon, the episode is called "Show Stoppers."
Yes. She isn't in Sailor Moon much but she is still in it! :)
She never does, although that is very popular in fan fiction.
In episode 112, Chibiusa meets a strange girl named Hotaru Tomoe. This is her first real appearance, however, you do not see Sailor Saturn at all, just her civilain form as Hotaru. In episode 119, it is revealed that Hotaru is Sailor Saturn, the senshi of death and rebirth, and silence. But still, we do not see Sailor Saturn herself yet. We just know by now that she exists and Hotaru is her as well as the Messiah of Silence. In episode 125, Mistress Nine (The Messiah of Silence, and also Hotaru) calls upon Pharaoh 90 using the Sacred Cup. Then, just before the world is about to be destroyed, Hotaru breaks free. The black star symbol of the Death Busters on Mistress Nine's forehead is shattered, replaced by the glow of Saturn's symbol. With Mistress Nine destroyed, we finally get to see Sailor Saturn in her true form. But she ends up sacrificing her life to stop Pharaoh Ninety, and is reborn as a baby. This is the first, and last, time we see Sailor Saturn in the S season. Those three episodes coud all be marked as Sailor Saturn's first appearance. However, in episode 168, Hotaru is reawakened as Sailor Saturn. We see the original Sailor Saturn as Hotaru is once again awakened and given her memories... then, later in the episode, Super Sailor Saturn makes her first appearance with the other Super Sailors Uranus, Neptune, and Pluto. If I gave a little too much information, I apologize. But I marked the milestones of Hotaru's first appearance, when it is discovered that she is Sailor Saturn, her first appearance as Sailor Saturn, and her first appearance as Super Sailor Saturn. ^^ Hope this helps you.
Rini transforms into Wicked Lady in episode 78.
In the original publication run of Sailor Moon, act 25 in volume 8 featured the first appearance of Sailors Uranus and Neptune, along with Chibiusa's meeting of Hotaru. There is no anime episode exactly equivalent to the events shown in this arc, but episodes 90 (Sailor Uranus and Neptune's first, shadowy appearance in the anime) 112 (Hotaru's first appearance and her meeting with Chibiusa) come very close.
The sailor scouts go to the moon in episode 40 or 41 of Sailor Moon.
Episode 132
There isn't an episode in which all of the sailor scouts are kidnapped. The closest to a kidnapping would be in Sailor Moon R when Sailor moon is aducted by Prince Diamond and the is episode 83
They find out in episode 109 of Sailor Moon S
Sailor Moon helps Sailor Saturn defeat Pharaoh Ninety in episode 125 which is part of the third season of the series Sailor Moon S
What episode does sailor moon use crisis power