Will CPFP work in unconfirmed input/output chain

[TruBitMil]

And how would it affect the fees required?

[ranochigo]

If you are talking about a whole chain of transactions which is unconfirmed and linked (ie. the inputs are the outputs of the transactions in the chain), then yes. CPFP will work for transactions which are linked only. Transactions that diverge from that chain would not be included.

For CPFP to work, miners must first be incentivised to mine it for you and the transaction chain takes space. The longer your chain, the more fees you have to pay for your child transaction.

[Thirdspace]

The longer your chain, the more fees you have to pay for your child transaction.

exactly as he said. just think of the whole chain as one big transaction.
add up their tx sizes and calculate the total required fee based minimum fee minus already paid fee
lets say: txA 500 bytes fee 5000 sats (10s/B) , txB 500 bytes fee 10000 sats (20s/B) output from txA used as input in txB,
so you want to do CPFP using output from txB as input in txC, with your txC 250 bytes
assuming current minimum fee is 300s/B then the fee would be:
( (500+500+250 B) * 300 ) - 15000 = 360000 sats (0.0036 BTC)
please cmiiw... 

[TruBitMil]

Thank you very much for the response guys - that was exactly what I was after