If one were to say, send a birthday card to a certain Arashi member for his upcoming bday...what would be a rule of thumb for keigo use or whatever? I would really prefer not to use it since I kind of suck at it, (plus there's no need to create extra distance if I'm already across the ocean, right?^^) but are there any birthday-related sentiments that would come across as rude or insulting if not phrased in keigo? Other than that I was planning on using desu/masu form, does that seem appropriate in terms of addressing an idol? [I'm just curious because in the letters fatured in junstyle I've heard a smattering of a couple levels of politeness, so I'm not sure and don't want to come off as a jerk.] Thank you so much for your help everyone!!
I know this is just on the very edge of relevance to this community here, but since it is about fanmail I was hoping it would count. If not, delete away and you have my apologies.