YES, thank you
@Odona Kirk. It's Metamorphosis.
Hint 1: all the clues are about one person.
All clues directly involve Assistant Federation Commissioner Nancy Hedford.
Hint 2: the last clue really tells it all.
"Companion" is given in the last clue.
1st Clue: Blame Starfleet for the problem.
NANCY: Small thanks to the Starfleet.
MCCOY: Now really, Commissioner, you can't blame the Starfleet.
NANCY: I should've received the proper inoculations ahead of time.
2nd Clue: A little hot under the collar.
McCoy was worried that she would develop a fever as the first signs of the disease. During the episode, she indeed develops said fever. The clue also refers to her continued anger during the episode.
3rd Clue: A little transparent.
Reference to both the Companion's appearance, and later when she looks though her transparent scarf.
4th Clue: Not dead, yet.
On her death bed, the companion merged with Nancy which brings her to perfect health.
5th Clue: A dual personality.
After the merger, both Nancy and the Companion are inside her body/brain.
6th Clue: <Sniff.> Maybe I really need to freshen up.
COCHRANE: Marooned, I told you. Look, we'll have lots of time to learn about each other. I have a small place over that way. All the comforts of home. I can even offer you a hot bath.
NANCY: How perceptive of you to notice I needed one. 
7th Clue: First I'm disgusting, then I'm beautiful. Half of me likes it.
When Cochrane learns that the Companion is feeding off him in a lover relationship, he says:
COCHRANE: That thing fed on me. It used me. It's disgusting.
Later after the merger, their conversion goes as:
COCHRANE: You're very beautiful.
NANCY: Part of me understands. Part does not. But it pleases me.
8th Clue: I'll have love and companionship until I die. (I running out of clues...)
Condensing the following dialog:
SPOCK: But you will age, both of you. There will be no immortality. You'll both grow old here and finally die.
COCHRANE: That's been happening to men and women for a long time. I've got the feeling it's one of the pleasanter things about being human, as long as you grow old together.
KIRK: Are you sure?
COCHRANE: There's plenty of water here. The climate's good for growing things. I might try to plant a fig tree. A man's entitled to that, isn't he? It isn't gratitude, Captain. Now that I see her, touch her, I know that I love her. We'll have a lot of years together. They'll be happy ones.
And last, I put reference to the
Companion in the clue, which I hoped would trigger the correct answer so I can pass the game on. Whew.
