What sort of biscuits are we talking about anyway?
1.004 would be about right with a fair whack of dextrose in the bill. You probably didn't need the maltodextrin in an all grain batch - just pure malt would have done fine.
All i can think is that you've picked up some spoilage somewhere along the line for the taste, as for the color that the calculations were wrong, got poor efficiency (doesn't look like it with 1.052 og though) ?
Not sure how you'd get down to 1-2 EBC, that'd be the palest beer ever - 6 EBC is about a Helles which is very light, around 8-10 EBC would be a standard aussie draught lager/Coopers Pale Ale colour.