The major issue with your model, and all other models for that matter, is the nature of the relationship, if any, between Ediacaran organisms and modern animals.

The ediacarans lived between 575 to 565 million years ago, and had disappeared by 540 million years ago. The Cambrian explosion revealed organisms, clearly related to modern animals, and occurred ~530 million years ago.

Careful analysis of fossil ensembles suggests that ediacarans, whatever their nature, were non-motile (see Narbonne, 2005).

It is not clear how one goes from non-motile ediacarans to the various types of motile organisms from which modern animals are descended.

There is evidence, however, for bilateral, worm-like organisms, present in ediacaran fossil formations.

These are recognized not by body fossils (in fact there are none), but rather by the presence of burrows through the sediment. These burrows indicate active movement, grazing and predation.

Current thinking, I believe, is that if ediacarans have modern descendents, they would be related to the sponges (porifera).

While it is impressive how many conclusions can be drawn from the type of careful analysis described by Narbonne, one critical piece of evidence that is missing, and impossible to get, is information on the organisms' genes.

Genomic data has been critical to resolving phylogenic relationships (see Field et al., 1988; Ruiz-Trillo e al., 1999). For example, it revealed that organisms as dissimilar as fruit flies, mice, and humans use similar signaling and gene regulatory systems to establish their major body axes.

Gene and genomic data would be essential to unambiguously resolve the relationship between ediacarans and other animals (assuming that ediacarans are animals), but at the moment, they appear not to be one of our ancestors.