[Ethereum] Truffle SWARM and IPFS Integration

IPFS currently doesn't have any in-built feature for providing access control. But as you said, you can always encrypt your content before adding it to IPFS and then give the keys to people you want to be able to decrypt the content.

You can add the constructor parameters as extra arguments to the deploy() call

const BaconMaker = artifacts.require('./BaconMaker.sol')

module.exports = (deployer, network, accounts) => {
  const userAddress = accounts[3];
  deployer.deploy(BaconMaker, userAddress)
}

In your case since Farm will create BaconMaker on demand, you do not have to deploy BaconMaker from the deploy scripts.

There's no general solution that fit all situations. Sometimes you create a single contract that will deploy child contracts. Also you can deploy several contracts and add them to a register after deployment, so they can communicate with each other.

A single contract is easiest, but you are bound by the block gas limit. Having several contracts is more complex because it no easy to communicate between them and you have to be more careful with the organization.