Question about Lidelle's speech

As you discussed in a prior question, you guys had a bit of trouble with translating Rulue, Raffina and Witch due to their speech patterns not being easily translated. Did Lidelle prove to be a challenge regarding how she speaks to Satan? As far as I'm aware(which doesn't say much), there's no easy way for onii-sama to be translated while still maintaining Lidelle's politeness. How did you manage to pull it off?

Lidelle didn’t prove as much of a challenge since her speech patterns are unique among the cast (dropping off mid-sentence, stuttering often), so the main thing we had to watch out for was making sure that she didn’t sound too stilted.

A note about Lidelle’s politeness is that she actually doesn’t use Sonkeigo or Kenjougo often, primarily relying on Teineigo. In other words, she’s polite but not as polite as she could be, something the earlier games played more with by making her unintentionally rude or cheeky at times. 

There aren’t actually many options for onii-chan / onii-san / onii-sama; they all have to be some variant of “big brother” (excluding the times when you might use onii-san as a word for “young man”, since that’s not the context here). Lidelle uses onii-sama, which is more polite and carries a sense of admiration, but it would be weird if we had chosen something like “dear older brother”. We opted for “big bro” (and “big sis” for Draco) as it sounds more endearing and intimate, which is exactly what Satan takes offense to.