Hi,
First of all, I was under the impression the other photographer was there simply as a guest or even was just someone they showed your photos too after the fact. I was unaware reading your earlier post that he too was shooting. That changes things a lot and, being the case, he's simply trashing you so he can sell them his stuff instead.
Perhaps he's not a regular wedding photog, didn't have a portfolio to pitch his work and simply offered to "shoot for free and without a contract, they only pay if they like something he gets". Or, even if he's an experienced wedding photog, maybe he didn't get in the loop until after they signed a contract with you, and they are now trying to make your life miserable enough that you'll let them out of it, under threat of a small claims suit or something like that if necessary, so they can buy from their friend. At any rate, he's selling his stuff by bashing your stuff.
Trashing a competitor happens, but is a very bad idea that more often than not comes back and bites you later. So, I simply wouldn't worry about that, other than dealing with the specific points brought up.
My dial up connection is going to time out long before I get to see the many shots you posted... Even if I could see them all, it's a very subjective thing so no one can really say "good" or "bad" and make any sort of make a judgment call for you.
Instead I'm just going to ask if the work is representative of what you showed them in your portfolio when they hired you.... You say it's better than your earlier work, but the question is if it's different? If it's similar, then they chose you because of your style and technique and they have no room for complaint (and the problem is the other issues noted above). If it's not like your usual work and stylistically different from what you showed in your portfolio, then there may be a valid basis for their request that you re-shoot some of the stuff.
Oh, and if I were you I'd worry about not having a clause in my contract preventing another photographer from coming in and disrupting things like that (I'm assuming you don't have such a clause, or you would have exercised it). He was not only impacting the wedding ceremony, I'm sure he was also getting in your way as you tried to do your job and fulfill your contract.
It's time to do damage control, fix what you can, learn from this and move on. It won't be the last time you have a glitch. What's more important is how you deal with problems when they come up, since it's unavoidable you will have some from time to time. Take the high road and you'll be okay.

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