Considering gaelic names have and continue to be used by english speakers with their correct pronunciations for thousands of years now, I doubt that by 3300 we'll have seen their proper usage completely vanish, particuarly when the space faring age of Elite Dangerous is relatively recent. You also have to take into account that the Empire is a particularly tradition orientated culture, and as such it would seem likely that they have a fair amount of consideration for the 'correct' pronunciation of traditional names.
In game lore also says that Imperials speak with a "quirky accent", and that's a quote direct from the game.
There's also some thought that the Empire is modelled on ancient Rome - see use of Latin names, etc. - which could plausibly support a pronunciation of "Aye-z-ling" or "Aye-sling" since Latin pronunciation adheres to spelling.
In all seriousness though this is a futile debate. Have you asked Aisling how she pronounces her name? Because she's the one who gets to decide how it's pronounced. Like I said, there are people with names from other cultures who pronounce their own name differently to the langauge it originated from. Sometimes deliberately so - I've known people named Sarah who pronounce their own name "Sara", people named Niamh who say their name is pronounced "Ny-eem-a". It's a deliberate, personal choice. It's a name. They're allowed to spell it and pronounce it however they want to, it doesn't matter what the original commonly accepted spelling or pronunciation was. So, like I said, only Aisling herself can resolve this debate - therefore the whole debate is not going to be resolved by us here.
