I pronounce them the same, but there isn't really a long "ah"/"aw"/"ar" sound for "a" in my accent anyway.
I prefer the spelling
Liliana. The name is already very fussy, without any more unnecessary letters. If I had to pick though, I'd choose Lillianna :-)
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"You are never given a wish without also being given the power to make it true."
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Elinor♥