All European banks I know require you the enter the recipient's name. So they could do a plausibility check, even with some spelling inconsistencies allowed. But banks are not in the business of offering good customer experience, they just put to their fineprint that only the number will be used. With IBANs there is only a 1% chance that the check-digits match (less if you weight common human typos), but still mistyping it and ending up with a valid number can realistically happen.
Yes it would, since adding a check digit means there are 10x as many numbers as possible accounts, and any single digit typo or transposition can't map to a valid account number with a valid check digit.
Even if a transfer doesn't go through, that transfer might be stuck pending for hours or days before being reverted, if we're talking about bank transfers.