The theory with the dreamfeed is the importance of not disturbing their sleep cycles to get them to eat. If they wake up, you've shot the whole night. The deepest, most restful sleep is right at the beginning, and they can't seem to get back there until they are older. If you disrupt that deep sleep, they are overtired, and can't put themselves back to sleep and wake every hour like you describe.
Absolutely put your baby to sleep if they are tired. And hopefully you are napping today too. Listen to him, feed him when he is hungry, and back off the solids if you think they are giving him a tummy ache. Solids are so iron fortified that can be incredibly constipating! That is why we go slow. And at this age he should only have a couple teaspoons of solids. If he has any more than that, he won't want his milk, which is what he needs. Make sense?