Several of the login reward cosmetics have been available again later on. I'm not sure if all of them have, but only because I haven't looked them all up. But for example the Dusky Fennec Fox was originally a login reward, then it was added to crown crates.

But I don't think there's any way to predict when that might happen or how the hair style will be available. The best thing to do is check the crown store showcase at the start of each month and when new crown crates come out check through them to see what's available.

Some things are only in the crown store for a few days, so sometimes I've set reminders on my phone for when they'll be available, especially if it's a time when I'm likely to be busy or away a lot, so I remember to log in and get it when I can.