frawjōn

• The Cantware weren't Anglish. When you claim "still apparent in West Flemish today", I would appreciate some sources that West Flemish had h-deletion at the time, because it also happens that Kentish lost h-. Some of the dialects I speak, don't pronounce "h-" either, but I wouldn't write "hik" (unless for a hiccup). Considering ellærn#Old English and Holunder#German, some dialects of Old English had already dropped h- in some words.
• But why would one only write 'z' for 't' at some places? Especially when those places often coincide with the High German consonant shift, I would expect a High German speaker (or at least a High German writer). Nicoline van der Sijs says "Daarbij heeft hij sommige woorden in het Oudnederlands omgezet, andere in het Oudhoogduits laten staan", though she expects a spreaker of Dutch. That's not very solid ground on which to build the hypothesis of a separate language.
• Oh yes, there is a definition of Old Dutch, it's every piece of Late West Germanic which can't be proven to be another LWG dialect/language (een deel van de woorden is dat wel, of in ieder geval kan niet bewezen worden dat ze het niet zijn).

I admit that Old Dutch, Old Saxon and Old High German can be considered three languages, I just consider the distinction anachronistic. You seem to group dialects as a language based (too often, IMHO) on current political borders (like Old Dutch isn't Old German, but Old kentish is Old English). One can file "urov", "urowen", "uruwen", "urowen", "urowe" and "fruwe" as frouwa, but preferring the starting 'f' (over 'u'/'v') seems like rolling with a loaded dice to me.