Looking for boy or girl names to go with [name]Justin[/name] and [name]Alexa[/name]
Girls:
[name]Eva[/name]
[name]Emma[/name]
[name]Julia[/name]
Boys:
[name]Declan[/name]
[name]Jack[/name]
[name]Gavin[/name]
BOYS
[name]Thomas[/name]
[name]Harry[/name]
[name]Jackson[/name]/[name]Jaxon[/name]
[name]Mason[/name]
[name]Matthew[/name]
GIRLS:
[name]Ruby[/name]
[name]Katie[/name]/[name]Katy[/name]
[name]Amy[/name]/[name]Aimee[/name]
[name]Caitlin[/name]
[name]Sophia[/name]
some ideas from my sister…
boys:
[name]Owen[/name]
[name]Matthew[/name]
[name]Daniel[/name]
[name]Caleb[/name]
girls:
[name]Lucy[/name]
[name]Carly[/name]
[name]Daphne[/name]
[name]Hi[/name]! I can see either popular (or getting popular) or modern sounding names with [name]Justin[/name] and [name]Alexa[/name], like:
[name]Audrey[/name]
[name]Brooke[/name]
[name]Chloe[/name]
[name]Grace[/name]
[name]Keira[/name]
[name]Lily[/name]
[name]Mallory[/name]
[name]Mia[/name]
[name]Natalie[/name]
[name]Paige[/name]
[name]Zoe[/name]
[name]Andrew[/name]
[name]Daniel[/name]
[name]Luke[/name]
[name]Lucas[/name]
[name]Matthew[/name]
[name]Nicholas[/name]
[name]Ryan[/name] (has [name]Justin[/name]'s N ending, though, which may or may not bother you…)
[name]Spencer[/name]
[name]Zachary[/name]
I’m sorry for repeats!
Good luck! 
[name]Edit[/name]: From your list, I can see all of the boys’ names with [name]Justin[/name] and [name]Alexa[/name], and from the girls’ names, I can see [name]Carly[/name] with [name]Justin[/name] and [name]Alexa[/name], but not [name]Lucy[/name] or [name]Daphne[/name], because to me, they feel vintage in comparison to your kids’ more modern sounding names. (Between [name]Lucy[/name] and [name]Daphne[/name], I can better see [name]Lucy[/name] with [name]Alexa[/name] and [name]Justin[/name], though.)
Good luck!
Girls:
[name]Daisy[/name]
[name]Phoebe[/name]
[name]Melissa[/name]
[name]Zoey[/name]
[name]Cecily[/name]