i find that you don't need to puree lentils as they go so soft once they've been soaked and then cooked, chickpeas need to be mashed or pureed though as they are quite hard, you'll need lots of water to go with the chickpeas (save the cooking water) as they are quite dry, even once they've ben cooked.
my dd is nearly nine months and is managing well with lumps as well as the husks of the lentils, so hopefully your lo will too.
hth