My daughter was so much like your son, and still is. She never ate a lot or drank much. She's always been in the 10th percentile as well. She only drank up to 4 ounces of formula/breast milk. When she was 9-10 months old we struggled with her bottle filling her up so much, that she stopped taking solids, simply b/c she wasn't hungry enough. After 10 months our pediatrician said to limit the bottle. Of course you would want to talk to your pediatrician first. (I noticed you said that he doesn't eat too much table food, so I thought of this past experience.)
Some ideas for table food: If he gum chews really well
Edamame ( my daughter still loves these, you just have to pop them out of the shell - you can buy these frozen at grocery stores, Trader Joes, or Whole Foods)
Frozen carrots, after you warm them up, they are easy to cut up small and are really soft
Earth's Best makes some great cereal bars, you can cut them up really small
Turkey meatballs, can be cut up really small (can get them at Trader Joes)
Frozen sweet potatoe fries (I believe they are organic, found at Target)- can be cut up really small as well
Also a tip that worked for us. I started to eliminate a snack, b/c my daughter is such a small eater that eliminating the snack made her hungrier for her lunch or dinner.
Hope at least one of these ideas work for you! I'm always searching for new things for my daughter, b/c rarely will she try anything new. Good luck!