Configure Bitcoin full node in my local LAN

It is said that deploying a Bitcoin full node would protect the privacy of my Bitcoin addresses.

Only to some extent. It is true that at least some employees of any business providing custodial wallets know a lot about the person associated with each address in their wallets. It is also true that nodes relied on by a simplified payment verification (SPV) wallet also know more than normal about the wallet holder.

However there's information in the public blockchain which is amenable to some forensic analysis that a sufficiently resourceful person or organisation can use to penetrate privacy to some extent.

If I configure a Bitcoin full node to be outbound only, would that be enough to protect me?

I doubt it has much effect on privacy regarding addresses used in transactions.

Do i still need to have a public IP address? (Since no other full node will connect in, do i still need to configure/supply a public IP address?)

No.

You might want to investigate whether your router supports UPnP and the implications of that.