Yes, these names are dated/trendy, and I think it’s great that you’re open to some wonderful classic/vintage/stylish alternatives!
In the end, you need to choose a name you love, regardless of its classification, but I still applaud your willingness to explore! 
[name]Amy[/name]: [name]Amelia[/name], [name]Adeline[/name], [name]Adelia[/name], [name]Audrey[/name], and the following trendy options: [name]Avery[/name], Ainsely, [name]Ashby[/name]
[name]Nicole[/name]: [name]Nicola[/name], [name]Noelle[/name], [name]Nora[/name], [name]Natalie[/name]
[name]Jennifer[/name]: [name]Genevieve[/name], [name]Gemma[/name] ([name]Jem[/name]-ma), [name]Georgia[/name], [name]Georgiana[/name]
[name]Melissa[/name]: [name]Matilda[/name], [name]Miranda[/name], [name]Marissa[/name]/[name]Marisa[/name], [name]Francesca[/name], [name]Larissa[/name], [name]Clarissa[/name]
[name]Megan[/name]: Try another name with a smilar feel, such as [name]Bronwen[/name]/[name]Bronwyn[/name], [name]Margaret[/name], [name]Maisie[/name], [name]Marin[/name]/[name]Maren[/name]
[name]Caitlin[/name]: [name]Catherine[/name], [name]Katherine[/name], [name]Kate[/name], [name]Charlotte[/name], [name]Caroline[/name], [name]Clementine[/name], [name]Chloe[/name], [name]Claire[/name], [name]Clara[/name]
[name]Emily[/name]: Although it’s overused, [name]Emily[/name] is a classic name, and will always be a classic. [name]Emmeline[/name] is a lovely alternative, as is [name]Amelia[/name].
[name]Jenna[/name]: [name]Gemma[/name] ([name]Jem[/name]-ma), [name]Genevieve[/name]
[name]Chelsea[/name]: [name]Charlotte[/name], [name]Chloe[/name], [name]Caroline[/name], [name]Celia[/name], [name]Cecilia[/name]
[name]Lisa[/name]: [name]Elizabeth[/name], [name]Eliza[/name], [name]Lila[/name], [name]Lily[/name], [name]Louisa[/name], [name]Lydia[/name], [name]Laura[/name], [name]Anneliese[/name]
[name]Carrie[/name]: [name]Caroline[/name] (you can still use [name]Carrie[/name] as the nickname it is)
[name]Shannon[/name]: [name]Rhiannon[/name], [name]Aveline[/name], [name]Bronwyn[/name]/[name]Bronwen[/name], [name]Darcy[/name], [name]Fiona[/name], [name]Maeve[/name], [name]Quinn[/name], [name]Tiernan[/name], [name]Sophie[/name], [name]Simone[/name], [name]Scarlett[/name], [name]Sasha[/name]
[name]Brooke[/name]: [name]Blythe[/name], [name]Bryn[/name], [name]Belle[/name], [name]Claire[/name], [name]Eve[/name], [name]Faith[/name], [name]Grace[/name], [name]Hope[/name], [name]Jane[/name], [name]Kate[/name], [name]Maeve[/name], [name]Mae[/name], [name]Nell[/name], [name]Paige[/name], [name]Quinn[/name], [name]Rose[/name], [name]Tess[/name]
[name]Kimberly[/name]: [name]Katherine[/name], [name]Keira[/name], [name]Kirby[/name], [name]Karenna[/name]
[name]Christina[/name]: [name]Christina[/name] is a lovely classic name.
[name]Kristin[/name]/[name]Krista[/name]: [name]Christina[/name]
[name]Heather[/name]: [name]Daisy[/name], [name]Violet[/name], [name]Delphine[/name], [name]Rose[/name], [name]Lila[/name], [name]Lily[/name], [name]Laurel[/name], [name]Linden[/name], [name]Willa[/name] (other flower/tree names…), [name]Helena[/name], [name]Hope[/name], [name]Hazel[/name], or the trendy [name]Hadley[/name]
[name]Lauren[/name]: [name]Laura[/name], [name]Laurel[/name], [name]Lorelei[/name]
Best wishes to you!