NN [name_m]Cass[/name_m] or CJ.
We are in the UK.
Other kids are [name_m]Milo[/name_m] [name_m]James[/name_m] & [name_f]Sunday[/name_f] [name_f]Jane[/name_f] 
Have to be honest I’m not overly keen on [name_m]Castle[/name_m] but this combo is lovely. [name_m]Cass[/name_m] or CJ make for great nicknames & it flows lovely with your other kids names 
[name_m]Castle[/name_m] is such a guilty pleasure of mine! I tend to not love [name_m]Jude[/name_m] personally but I think it sounds really nice as a combo. I would totally go for it- I think [name_m]Castle[/name_m] has a lot of untapped potential and I would love to see someone use it (especially with [name_m]Milo[/name_m] and Sunday!)
It’s not my personal style, but I think it works well with [name_m]Milo[/name_m] and [name_f]Sunday[/name_f]. Especially like the nickname options!
I really like it
This combo is really doing it for me! I’m not sure if I’d be brave enough to use [name_m]Castle[/name_m] myself, but I adore it. Some [name_m]Castle[/name_m] [name_m]Jude[/name_m] sounds so natural and right. [name_f]Sunday[/name_f] and [name_m]Castle[/name_m] are siblings that are made for each other too!
[name_f]My[/name_f] overall answer is that the nicknames and middle name ground [name_m]Castle[/name_m] enough to make it a yes from me.
It is very cool and unexpected - I quite like the rugged vibes and distinction
i like it! it is unique, and sounds great with the sibset.
Very cute! I love the nickname [name_m]Cass[/name_m].