I love, love, love Llyr/Lir. I think if you're worried about pronunciation, I'd go with
Lir, even though the 'i' may trip a few people up.
Even though my name is
Alexandria, I get called
Alexandra constantly. It's not the same, people say it correctly, but they still don't get it right. I think it's something that you just have to take in stride, and once you correct someone once, it's not a huge deal.
Also, if people don't think it's a real name, tell them to look it up! It's completely usable, adorable, and fits well with
Freya and
Ronan, which are also great names.