Children with a seat, yes, the full amount. Lap infants are arguable.
Check your flightFully entitled, exactly like an adult. Compensation is a fixed amount per passenger and it has nothing to do with what the ticket cost, so a child on a discounted fare is owed the same €600 as the person beside them who paid full price.
This is what makes family claims large. Four people on a delayed long haul flight are owed up to €2,400. Six are owed up to €3,600.
This one is genuinely less settled, and anyone telling you it is clear cut is overstating it.
Article 3(3) excludes passengers travelling free of charge or on a reduced fare not available directly or indirectly to the public. Airlines lean on this to refuse lap infants.
The counter argument is that an infant fare, usually around ten percent of the adult fare plus taxes, is publicly available to anyone who books it. If you paid something for that infant and they have a ticket number, that is not travelling free of charge, and the exclusion is aimed at staff travel and prize tickets rather than paying customers.
Practical position: if the infant was ticketed and you paid a fare, claim for them and make the airline argue the point. If they genuinely travelled free with no ticket issued, expect a refusal that will be hard to shift.
Expenses are separate again. If the delay forced you to buy meals, nappies or overnight essentials, those are duty of care and claimable on top with receipts.
Work out the family total