Just noticed that she was using his name before they were married: they were married in May 2014, but she's used Burgess on
this profile, which was last changed earlier in 2014. Also, it indicates she'd bought the domain name shannonhburgess.com.
Maybe she took his name because she preferred the sound of it, professionally, over Madill?
I'm still thinking that LE, her family, and friends have evidence that leads them to believe she left willingly---her family pleads for her to contact them, LE has said that she could be in Toronto or Vancouver, and on one of the LARP FB pages, there's something to the tune of "I hope she's just taken some time to unplug." Her last three FB posts indicate she was having a rough month---the post about her brakes insinuates it was just one of several bad things to happen, the Blank Spaces reference indicates relationship problems, and the "We're adults & busy. No reason to be in constant contact with you to prove my friendship to you. Just know when/if you need me, I'm here," suggests some conflict over communication.
The dog is an interesting point. She did go to Edmonton just prior to disappearing, would it be possible that while away,she'd left the dog with family or JB, who was staying somewhere else? And the dog stayed there in the 5 days it took for anyone to notice she was missing?
Even if she did leave willingly (which I really hope is the case), it doesn't mean she's safe.