Our two sets of neighbors have babies named [name_f]Charlotte[/name_f] and [name_m]Charles[/name_m]! What would you think about us naming a possible girl [name_f]Caroline[/name_f]? They would all be very close in age!
I think it would be kind of clever though most non-name nerds probably wouldn’t notice 
It’s not an issue. You can’t guarantee you or they will live in the same place forever and many people probably don’t know the connection between [name_f]Charlotte[/name_f] and [name_f]Caroline[/name_f].
I voted the two least popular options. 
I doubt most people know the names are related
Also, when we think of neighbours [name_m]Charles[/name_m], [name_f]Charlotte[/name_f] and [name_f]Caroline[/name_f]; the similarity [name_m]Charles[/name_m] and [name_f]Charlotte[/name_f] is definitely more noticeable and more likely to gain attention so I doubt anyone will care about [name_f]Caroline[/name_f]