If I transfer money into my Blockchain account after receiving my Json wallet backup by email, would it restore recently added funds?
EDIT: According to this answer: Future addresses are not backed up, but you should have the option to receive a new email backup every time you make a transaction.
Without an official statement from Blockchain, you should assume that the backup does not allow you to restore future funds.
At the time of this answer, Blockchain states that they back up your wallet every 24 hours, which indicates they are probably not using deterministic wallets (deterministic wallets only need to be backed up once and can restore all existing and future private keys).
From the Blockchain.info Backups page:
Your wallet is automatically saved on at least two separate servers and is backed up to an offsite location every 24 hours.
Note that this answer also states that the "keypool" is not enabled on Blockchain, which means future addresses would not be backed up
Description of the keypool from en.bitcoin.it:
The wallet contains a pool of queued keys. By default there are 100 keys in the key pool.