Sacrament of the Lady:
Model generates double the amount of power dice but can not cast any spells. it is my understanding that the power dice generated by a wizard can only be used by the wizard so what is the use of this item?

Prayer Icon of Quenelles:
Icon can be reveled to grant the Lady's blessing to the bearer and unit she is with following the rules for the lady's blessing. Can you use this to give peasants the lady's blessing or will that not work because they do not have a knights vow ect.

in earlier editions of the rules (not 7th) power dice were generated and could be used by any caster in your army instead of specific dice generated for specific mages. It's something they'll have to fix when they redo the book (not that it need redoing anytime soon)

As far as peasants getting the blessing, I think most opponents would be leery of that. Since peasants normally can't have vows/blessings per rules of blessings. I think the answer is "no".

Strangely, the Sacrament still has the use of generating power idce to use for dispelling remains in play spells, though it is an expensive way of doing it. Probably only useful against a magic heavy Ogre army.

Not positive on the second Q, sorry.

1. Unless trying to generate extra dice for dispelling Remains in Play spells, this item is useless.

2. This item gives the Blessing of the Lady to any unit the Damsel/Prophetess is with when the Icon is revealed. Nowhere does it say that it does not affect peasants. A useful tactic for this is to put a prophetess inside a large unit of skirmishing bowmen and use the Icon.