Number two isn't really important and I don't see it as part of the basic knowledge of bitcoin because getting a good wallet that is an open source and self custody can be a problem to a new investor because wallet is technical. Since he is a new investor who wants to start his bitcoin investment with weekly DCA, he is to only open an account with a reputable exchange, buy bitcoin through p2p and leave his bitcoin in the exchange for the main time, while he continues to learn more about bitcoin and which wallet is best for him to use.

It's also important that when accumulating bitcoin, we don't buy bitcoin of $50 and send immediately to our self custody wallet in order to avoid many small small UTXO, which can suck almost all our profits in future if transact fees becomes very high. Good UTXO management is important as a bitcoin investor which is why you need to accumulate your bitcoin to a good amount up to $500 and above  in your exchange account before transferring it to your hardware wallet.