Freya's previous owner was most likely someone close to Greg. Most likely a family member.
Greg and Shiloh's adoption of Freya was briefly announced in the video "I Respect Her Wishes" on June 23, 2011. After Shiloh lost 3 year of her memory, they adopted Freya together. ($ource) This was possibly Freya's only video appearance.
Greg uploaded the video "Strange Dog Behavior" on June 27, 2011 to his Speaks channel. Greg and Shiloh talk about how they caught their dog eating Shiloh's panties. Shiloh also mentions the dog has been going for her crotch recently. ($ource)
On July 8, 2011, Shiloh wrote a blog post titled "Weird dog behaviour." She explains that their dog had peed in her and Greg's bed the preious night. She says when she was cleaning it, the dog bit her in her crotch area. She thinks the dog's sudden aggression came from missing its original owners. (Source)
After Freya's brief appearance in Greg and Shiloh's online life, viewers began questioning what happened to the dog. There was even a rumor that Greg and Shiloh were only dog sitting Freya for a family member.
Greg uploaded "My Previous Dogs" on December 24, 2011 talking about Freya and OniShi. In the video, he explains he was asked to take Freya in by her original owners. He says Shiloh told him the dog "allegedly" bit her, even though he never saw it happen. He states he never thought the dog could bite anyone. Since it bit her, they had to give Freya back to her original owners. ($ource)
When Adrienne's email talking about her relationship with Greg was leaked, people began talking about Freya again. Adrienne claims Greg told her strange things his mother claimed Shiloh had done with their dog. "he even went as far as to tell me that his mother informed him that when they were broken up but still living together [...] Shiloh tried to force his little dog to eat her out, and the dog got scared, so it bit her in the crotch. Then he said something about Shiloh peeing on his bed and blaming the dog?"
On November 20, 2011 Greg uploaded "Where's Freya?" to his Speaks channel. He starts off the video by saying "some total idiot moron with a loud mouth" spread a rumor that Shiloh let a dog lick her vagina. He says anyone that believed the rumor is an idiot. He says he told this person Shiloh was only accused of letting a dog lick her vagina, but the "total idiot moron who cannot listen" decided to spread the rumor. He says he never owned the dog and it's with its real owner. ($ource)
It is very plausible Greg's mother started the rumor, as she publicly showed her dislike of Shiloh often. (Source)