Don't know if it's just me, but doesn't her 'inniu' sound like inniubh? Slight 'v' sound at the end to my ears.
The sentence doesn't make any sense to me. Does the sentence actually mean "Are we welcomeD today?"
No, it means “Are we welcome today?”. The noun fáilte in this idiom is translated as the adjective “welcome” rather than the verb “welcome”; if the question were changed to a statement, Tá fáilte romhainn inniu would translate as “We are welcome today”.