Few things I would be concerned with this plan:
1. Clogging the plate chiller/heater - a grant with some type of filter in line before the drain (in the grant) could catch some of the early grain particles prior to grain bed setup.
2. Stuck Sparge/Recirculation - a grant should fix that.
3. Lactobacillus (from your mash runnings) in your plate chiller - could be killed off with recirculation of your boiling wort prior to chilling, though is that worth the risk? I know my March pump doesn't like pumping boiling liquid (too many bubbles).
Disclaimer - I do not currently recirculate mash or wort as my setup isn't quite there yet, so this would be mostly theoretical and based on wisdom procured within HBT.
Like where your headed though...