I don't think you have to have the premium vouchers if you're staying at the DLH. When we stayed there last year we just had the Plus ones.
The DLH has a fantastic buffet breakfast so if you really fill up on this in the morning you probably won't want much until dinner other than the odd snack or a couple of counter service meals between you so the full board option probably would be too much food for you all.
Personally, I'm not a fan of the meal plans anyway as they limit the restaurants you can use if you want to get the full benefit from them. For example, you couldn't visit the Agrabah Cafe (standard) and Walts (Plus) in the same visit unless you just used the vouchers as a cash equivalent but then you wouldn't benefit from a discount.
As to which restaurants I'd recommend, that really depends on what you're looking for. We've been to...
Cafe Mickey - great atmosphere and a fun way to meet the characters. We didn't really rate the food or the service but still enjoyed it. Plus, you don't have to buy a full meal there - you can just share a couple of pizzas and still get to meet the characters
Agrabah Cafe - a buffet restaurant with a middle eastern theme so you'll find couscous, tagines/stews, salads etc. They also do child-friendly pasta/tomato sauce/meatballs
Inventions - we had lunch there so no characters (they only appear at dinner time) but the food is fab. Again, several child friendly options
Walts - very nice food and good service. It's a smart place but it's Disney so don't be afraid to go there with children
Blue Lagoon - good food and a fab setting right inside the Pirates of the Caribbean ride.
Have a look at the restaurant menus on DLRP Magic to give you more of an idea of what's on offer.http://www.dlrpmagic.com/planning/dinin
Oh, and don't forget your 1 year old eats for free.