Ahhh gosh as a mother of a daughter obsessed[name_f][/name_f] with frozen I had to respond!
[name_f][/name_f][name_f]Elsa[/name_f] is a lovely name and I have met Elsa’s in IRL so for me I do think the name is usable. She’s bright, elegant, has a lovely meaning and has this sunny yellow imagery. Furthermore [name_f]Elsie[/name_f] is definitely on the rise (I’ve met tons) so why can’t [name_f]Elsa[/name_f] be a more common feature?
[name_f][/name_f]However [name_f]Elsa[/name_f] will be associated with frozen. When my daughter met a real life [name_f]Elsa[/name_f] [name_f][/name_f] she was incredibly excited and kept referring to frozen. The girl named [name_f]Elsa[/name_f] [name_f][/name_f] was clearly born before the movie was created [name_f][/name_f] as she was around 16 years old. Luckily this [name_f]Elsa[/name_f] thought [name_f]Lilia[/name_f] was sweet and wasn’t bothered by [name_f]Lilia[/name_f] thinking she was in some way related to [name_f]Elsa[/name_f].
[name_f][/name_f]It’s hard to pinpoint why [name_f]Elsa[/name_f] appears to not be usable whereas the likes of [name_f]Jasmine[/name_f], [name_f]Aurora[/name_f] & [name_f]Belle[/name_f] are. [name_f]My[/name_f] thinking is that frozen is just so popular and has remained popular since the creation. Furthermore [name_f]Elsa[/name_f] has always been a rarer name without any popularity of something else associated if that makes sense. For example [name_f]Jasmine[/name_f] is a name that has always been popular along with being a floral name/common scent so you have lots of associations. Similarly [name_f]Aurora[/name_f] is also terminology associated with Northern Lights. In relation to [name_f]Belle[/name_f] she’s a popular sound anyways so doesn’t have an overtly strong [name_f]Disney[/name_f] feel. Whereas [name_f]Elsa[/name_f] feels rather singular in comparison so the only association is Frozen. Regarding her character [name_f]Elsa[/name_f] definitely isn’t a villain she’s an amazing character and most frozen enthusiasts would want to be [name_f]Elsa[/name_f]. I know [name_f]Lilia[/name_f] definitely puts on her multiple [name_f]Elsa[/name_f] dresses numerous times a day and when her friends are over they argue over who is going to be [name_f]Elsa[/name_f] today 
Personally I think [name_f]Elsa[/name_f] is a sweet name and is usable for a braver namer someone who doesn’t mind the frozen associations!