Were I Timy I wouldn't be trying to invoke the reasonable doubt standard. I'd hammer this one:
If Dashing Swordsman advances casting, that would be a house rule that Rich introduced. ITT, we assume Rich is using 3.5E D&D rules, even when we know he sometimes doesn't. Since the claim that Dashing Swordsman levels could provide casting can be included by adding "*or The Giant used a houserule", then it doesn't need to be included in the OP at all, because it is automatically included in everything we could possibly post.
But even if we pretend that stuff we make up whole cloth isn't a house rule because we attached it to a different house rule Rich has already confirmed, my question is why Dashing Swordsman is considered superior to Lyric Thaumaturge, or any other prestige class that also advances full casting. I'm gonna bring up that context thing again and suggest there's no context to suggest Elan took Lyric Thaumaturge, just like there's no context to suggest that Dashing Swordsman advances casting.
You're basically saying that evidence could appear in the future to settle the issue, and that future-evidence creates reasonable doubt. I'm not saying it's impossible, but if it never happens, if we never see Elan demonstrate a single new Dashing Swordsman ability until past the end of the comic, I would not feel like the smart guy if I'd been arguing that new Bard spells might represent new Dashing Swordsman levels, with no additional evidence. Nor would I feel especially dumb if I interpreted new Bard spells as new Bard levels and then had to retract what I said when Rich told us otherwise. You fooled me, Rich! Good job!
That being said, I still support 14+/1+ (16+), I just don't like what this thread does to "reasonable doubt."