They’re both nice names, and both work well with your boys’ names.
If both work equally well for you and your husband only likes [name_f]Freya[/name_f], then I’d suggest going with [name_f]Freya[/name_f].
If you don’t feel ready to let go of [name_f]Hazel[/name_f], perhaps that’s actually your favourite.
I don’t know which you should choose, but I thought I’d ask a few questions that might help you determine what it is you like about each name:
[name_f]Do[/name_f] you know which middle name you’d like to use (if any), or will it depend on the first name?
[name_m]How[/name_m] do they sound with your preferred middle and last name? Maybe try out a name test run: Baby Name Test Drive : BabyNameGenie.com
[name_m]How[/name_m] do you feel about [name_f]Freya[/name_f] [name_f]Hazel[/name_f]? [name_f]Hazel[/name_f] [name_f]Freya[/name_f]? Or with a second middle name: [name_f]Hazel[/name_f] _____ [name_f]Freya[/name_f]? [name_f]Freya[/name_f] ______[name_f]Hazel[/name_f]?
Maybe try googling the full name and see what comes up?
Does popularity make a difference to you? It might be worth looking up their popularity where you live ([name_f]Freya[/name_f]‘s more popular in the UK, [name_f]Hazel[/name_f] in the US).
if you live in the US, [name_f]Freya[/name_f] is closer in popularity to your boys’ names than [name_f]Hazel[/name_f] (though [name_u]Max[/name_u]‘s nickname makes his name more familiar). If you live in the US, [name_f]Hazel[/name_f] is closer in rank to your boys’ names.
Are nicknames important? [name_f]Hazel[/name_f] has Hazey, [name_m]Haze[/name_m]. [name_f]Freya[/name_f] has [name_m]Frey[/name_m], [name_f]Faye[/name_f]? Any others?
Are namesakes important?
[name_f]Freya[/name_f] reminds me of [name_f]Freya[/name_f] [name_m]Stark[/name_m] (http://www.fembio.org/english/biography.php/woman/biography/freya-stark/) ; [name_f]Hazel[/name_f] reminds me of [name_f]Hazel[/name_f] Lavery (Hazel Lavery - Wikipedia). [name_f]Hazel[/name_f] also has quite strong pop culture associations (the Fault in Our Stars).
Is the meaning of [name_f]Hazel[/name_f] important? Or the fact it’s a nature name?
Sorry for only giving you questions, but I think they’re both great names - the trick is to figure out whic you prefer. If you find you do prefer [name_f]Freya[/name_f], then the problem’s solved. If you like [name_f]Hazel[/name_f] best, I’m sure other Berries will have some good advice about how to discuss that with your husband.