Others would remember her if she didn’t modify their memories.
Memory charms only work on the specific person or people they’re used on - as long as Hermione hadn’t modified the memories of everyone who knew her, they’d all still remember her.
They wouldn’t find her parents, who had new names and moved.
While their memories were modified, Hermione’s parents wouldn’t be talking to anyone else who knew her because those people wouldn’t be able to find them - they’d moved and changed names. That was so the Dark Lord wouldn’t be able to track them, but it’d also then mean that their friends, neighbors, relatives, and other people who know them wouldn’t be able to find them either. Since Hermione’s parents wouldn’t remember them, and can’t be found, they wouldn’t be in contact with anyone they knew as Mr. and Mrs. Granger until Hermione unmodified their memories.
“I’ve also modified my parents’ memories so that they’re convinced they’re really called Wendell and Monica Wilkins, and that their life’s ambition is to move to Australia, which they have now done. That’s to make it more difficult for Voldemort to track them down and interrogate them about me – or you, because unfortunately, I’ve told them quite a bit about you.”
-Harry Potter and the Deathly Hallows, Chapter 6 (The Ghoul in Pyjamas)
For the time their memories were modified, Hermione’s other relatives as well as other people who knew her parents would probably wonder where they went, but they wouldn’t be able to find them to talk to them, so they wouldn’t know they’ve forgotten their daughter. Once Hermione’s parents got back in contact with the people they knew as Mr. and Mrs. Granger, they’d already remember everything, and they and Hermione could make up a plausible excuse for their sudden absence.