I can think of two rebuttals:
In the New American Bible, Luke 23:43 says, "He replied to him, ‘Amen, I say to you, today you will be with me in Paradise.’ "
In the original Greek, there were no punctuation marks. No commas. Not even periods. It was the sentence structure that told the reader where one thought began and ended. When this phrase was transliterated, it came out as shown above. BUT! It could have been, "He replied to him, ‘Amen, I say to you today, you will be with me in Paradise.’ " See the difference? In the first case, the comma is before “today”. In the second case, the comma is AFTER “today”. Each has a completely different meaning.
I saw a T Shirt once that read, “GODISNOWHERE”. Depending on how it struck you, it could be read, “GOD IS NOWHERE” or “GOD IS NOW HERE”. Same shirt, two different meanings. The same principle applies to this verse.
The other point is that we are bound by the sacraments, but GOD is not. He can admit into his kingdom whomever he wants. He can forgive all sins by any sinner at any time. He can bestow His grace at His pleasure. But, in absence of knowing God’s will 100% of the time, we have been given the gift of His Church to guide along our path until we meet Him face to face. I try to always be aware of this and not try to apply to God the laws given to man.
Bottom line, we are all his children and he can treat us all differently for anything, including eternal salvation. After all, all creation, all blessings, all eternity are His. We do not and cannot know His will 100%. To know that would make us His equal, or at least equal in His knowledge. Only one man fits that. And He was God, too!
Hope this helps.
Jeff