You can do a stocking with little bits and pieces. When my DCs were babies (both were younger than yours at Christmas) I filled their stockings with things like musical instruments (maracas and shakers) and bath toys. Don't bother wrapping anything in the stocking.
A couple of big toys otherwise sounds like plenty!
I did a stocking last year for DS who was 10 months, more for my benefit than his! He had socks, a couple of t-shirts, some bubbles, a bath toy and a musical instrument. I did put chocolate coins in (obligatory in any stocking in our family!) but I helped him out with those! We have some cute pics of him surrounded by wrapping paper looking slightly bewildered! My DM also bought some 'first Christmas' pjs and a present bag with his name on.