Alicia definitely remembers Percy from school and may have been chastised a couple of times by him or gotten in trouble courtesy of the twins. If things simply were that, she would probably still be seeing him as the git with the broomstick up his bum, however... things are not simply that. Alicia's twins, Isla and Liam, will be 6 this December, so there's always the single parent aspect (though yes, Percy does have shared custody over Lucy, but it's still something) and their kids are going to be in the same year at school, so :D
And Melinda (who I'm still trying to get ready to introduce), I doubt would really know Percy, other than he was a strict Prefect who dated one of the older girls from her house. She was Ravenclaw and is 3 years younger than Percy, and she runs Sweet Nothings, a pâtisserie in Monument Alley.