Tested

During the night (pick a watch, any watch) have the character on watch make a perception check DC20 to notice movement in the woods around the campsite, just beyond the reach of the light.
Lurking in the shadows are four brown bears and a werebear. Lured from their caves in the forest by the flickering light and the smell of fresh bodies, the bears have come to rummage what they can. The lycanthrope has been shadowing the party off and on up the river, and has finally managed to catch them alone out of town.
I don't know who this is, or why they might be following the party, but I like the concept. Tracking them up the hillside, she was nearly betrayed by the arrival of the bears, but they seemed to cower before her and yield to her guidance. Quickly, they found the campsite and surrounded the party. If the watch notices the bears' movement, they forego stealth and charge.
If they go unnoticed, have them roll a stealth check against the watcher's passive perception to gain a surprise attack. For their surprise attack, the bears will charge recklessly into camp growling fiercely, targeting any sleeping adventurers. The she-bear lycanthrope will rise to her full health, howl in a great terrifying roar intending to intimidate the party members. Have them roll a DC13 wisdom save or be stunned for one round. Once they know the bears are present and attacking, they can not be intimidated in this fashion again.
Because of the power of the nearby shrine, allow anyone trying to calm or control the bears rather than slaughter them make their attacks or checks with advantage. As for the she-bear, give her vulnerability to radiant damage, due to the protection of Lathander. Eric and Laramie will largely ignore the brown bears to attack the werebear.
In the event anyone contracts lycanthropy, the priests at the shrine may be able to help with that. If you'd rather let it play out within the campaign, the symptoms might not present themselves until a later date.