The church, in Church Avenue, opened to the public for the remembrance event between 10:00 and 16:00 GMT.
Claire Hickton, from the 4th Sutton-in-Ashfield Brownies, was among those who paid tribute to Grace, who was a young leader in the Brownies.
“I will remember her smile and her energy,” she said.
“She was infectious with the girls, they absolutely loved her,” she added.
“I just hope she can be found, so she can be reunited with her mum and there’s closure for her dad and the rest of the family.”
Nick Tennant, 67, from Kimberley, in Nottinghamshire, said he used to love going out for runs with his former colleague Sarah.
“I used to go running with her, it was an amazing time, because she was great to run with and even taught me how to run uphill,” said Tennant.
“She was lovely as a person. When people talk about her, I always think ‘I know exactly what you mean, she just lit up the room’.
“It is so sad, somebody so young and with so much to live for, it really has affected me quite a lot.”