Well I could not find anything from other eras for now, but I did find continuing stories for the ones that I found. This story shall continue from the Celtic era with Brandon from part 1.
...

In the age of old in Ireland, this very town is filled with headless people. They could no received help for people view them as monsters or dullahans. It has reached to the point that the world had forgotten this very town.

Though everybody sort of gotten used to their headless states. It just means that it's a common thing in the town now.

We see Brandon and Freya's heads being carried by Brandon's sister Aisling through the woods. Aisling apparently had the body of one of the strongest men in the village.

"Take us back Aisling! It's too dangerous." said Brandon's head.

"Where's your sense of adventure?" asked Freya's head.

"How can you even have one when we got no bodies?" asked Brandon's head.

"You want to find our bodies or not." asked Freya's head.

"Everyone! Be quiet! I hate it when you two argue for the past few days! I can leave your heads here if you like." threaten Aisling, "I am the one with the body and technically the older one."

"Fine Aisling." said Brandon's head.

"Nah uh uh. Remember what I told you about this body." said Aisling.

"Yes big sister." said Brandon's head.

"Tee hee." giggled Aisling.

Apparently, Aisling has this natural gift on being persuasive on bodies. While everyone has their bodies out of control, Aisling for some reason can tame them. Now with a single word, a body will do as she says. She even had the nerve to get herself attached to a powerful body despite the head's pleas. She could be punished, but Aisling does not care. She's the big sister for the day.

Suddenly, the group hear footsteps. Aisling places the heads of her brother and friend on the floor and drew her sword that the body so happen to have. She was sweating until she whispered.

"Hey big brother, can I ask you a favor?" asked Aisling.

"Yes, big sister." Brandon's head grumbled.

"Want to share bodies for a bit? It's not that I'm afraid, I just felt really bad for you." asked Aisling.

Brandon knew Aisling was afraid and decides to accept her offer. Aisling immediately puts Brandon's head on backwards.

"Aisling." scolded Brandon.

"Sorry." said Aisling.

"What about me?" asked Freya's head.

"Later." said Aisling as she adjusted Brandon's head.

"How do we use a sword?" Aisling, "I um was testing you."

"I don't know, just slish and slash." said Brandon.

"And Freya. You stay here while me and big brother look for what's stalking us." said Aisling.

"Like I can." replied Freya's head as she blows some hair off her long blond hair.

Aisling and Brandon, sharing one body, went off to find whoever is looking at them. With one arm, Aisling was slashing at anything while Brandon had to make sure that she is being careful.

"Aisling! You might have wounded us." said Brandon.

"Sorry. And you forgot..." said Aisling.

"We are sharing the same body so we are equal." said Brandon.

"Hmm, good point." said Aisling.

They kept looking until they found something that they never saw in a long time. A person attach to their original body. This person looked afraid of the conjoined siblings and screamed, "MONSTER!"

"You meany! You're the monster!" cried Aisling.

"Excuse us. We are in fact cursed people. We will leave." said Brandon while controlling both feet.

"Wait! My apologies. I was just shocked. Though I would like to ask what has happened to you." asked the man.

Brandon and Aisling sat down and explained everything that has happened. After sometime, the man got up and has written a few documents of Brandon's story.

"Well thank you sir and ma'am. I found myself an interesting story. Safe journeys everyone." said the man as he left.

"We better get home or our heads are done for." said Brandon.

"Yeah, and I'm also worried about Freya. What's she's doing now?" asked Aisling.

...

Freya's head has been sitting for a while looking bored.

"If there was someone I can talk to. Maybe a dullahan since we are both headless." said Freya's head.

With that, a dullahan appears. Freya's head grumbled over the fact that her words can cause trouble. The dullahan looks as if it was taking a break and places it's head next to Freya's head. The head has a red high pony tail hair and has a sharp figure.

"Ah, a fellow dullahan taking a break I see." said the dullahan.

"No, I am but a mortal's living head." said Freya's head.

"Wait. It can't be. That woman would never." said the dullahan.

"You mean the witch with purple hair?" asked Freya's head.

"Yes! She has harassed me and my dullahan friends. We tried to take her life since it's our job, but she always escape death. Now she is aiming for mortals and keeping them alive at a death state. She has cheated death so many times!" complained the dullahan head.

"What can we do?" asked Freya's head.

"I'm afraid there is nothing we can do for you. Though on the plus side, you will not age much, best be as a young woman only, and live forever." said the dullahan head.

"There's that." said Freya's head.

"Normally if you see me, I have to kill you, but since that woman got involved, you get to be spared and you had no control over this. Until then, farewell." said the dullahan as her body picks up her head and rode away on her horse.

"That was odd." said Freya's head.

"Freya!" cried Brandon.

"Brandon! Aisling! What took you two so long? I was so bored as a head. At least carry me with you. I find is exciting." scolded Freya.

"Sorry Freya." said Brandon.

...

Somewhere far away, Brandon and Freya's bodies held hands as they look for a place to get married. They look everywhere, but there was nothing. It was until they felt a pat on their shoulder that they looked back and saw a disturbing man.

"From the looks of it, you two wanted to be married, but you don't got mouths to say so." asked the man.

The bodies nodded.

"I was joking, but might as well. I may not look like it, but I am able to wed you two." said the man.

The two bodies look at each other, if you can call it that, and looked happy.