If you made those code changes before submitting to Apple, I would tend to think that isn’t the cause since they would have rejected at that point.
Looking through the podcast episodes, I did notice a few of them don’t have an author specified. I made a copy of the code in the feed and added an author and then uploaded it to my server. I then submitted that URL to iTunes via the File > Subscribe to Podcast option and it pulled the podcast up.
It might be that making sure that every episode has a speaker will do the trick. Here are a few that don’t have one currently:
The good news at the end of your rope
Is Christianity Just a Crutch?
I did a test submission of your feed in iTunes by going to File > Subscribe to Podcast and entering the URL to your feed there. When I tried that yesterday, I received an invalid feed error, but this morning it pulls up your feed just fine. I ran it through Apple’s recommended validator and it passed there as well.
You might try altering the URL slug of your feed a bit and resubmit with the new URL. You can do that by editing your page and changing the slug just below the page title. Perhaps they have the feed cached and they are pulling in old information. A slightly different URL would be a way around that.
If Apple is still rejecting your feed today, then I believe you’ll need to contact them and get a reason why. Those are the two tests that Apple gives us to use prior to submission. Since it passes both we’ll need some indication from them as to why it is being rejected.