Could Hallucigenia be the echinoderm missing link?

If you want it to be taken seriously, start by taking it seriously yourself. The proposal looks vaguely plausible on paper to this semi-informed layman, based on the extremely limited amount of data you’ve provided, but most of us don’t have the background to evaluate it properly.

I think it’s an interesting enough thought to be worth checking on; that is “taking it seriously”. I suspect you’re going to be disappointed, but I’d be delighted to see you gather the evidence and expert opinions to prove me wrong. So go do that. Please.

Getting the idea is where the process starts. Now you need to take it the rest of the way, or it’s storytelling rather than science.