
You will ahve to treat him like an 8 week old puppy, and act like he doesn't know what any words mean (which he probably doesn't really).
With the housetraining it is watch like a hawk and take him outsdie every half hour while he is awake. wehn you can't give 100% attention crtate him. Also clean any mishaps with biologicla washing powder dolution, and then goover with vinegar or similar to neutralise, so he isn't attracted to the same spots.
The barking is best dealt with by calmly distracting him. Saying no crossly or shouting at him will just make him think you are jointing in. both will be no good for over excitement or fear.
Wehn you see people approcahing get his attention on you (use a treat or toy, whatever he responds to best). Tell him to perform some behaviour, lik sit or down, and then reward for this. If he is reasonably calm I would quietly tell him to 'shush' and ensure compliance by holding his head gently and keepign him from barking and gently slowly stroking him to keep him clam, and reward with voice for compliance.
If the barking is through fear then your reaction must not come across as reasuring him, as then whe will thinkmthere really is something to be afraid of.
I often tell people that a Jolly Hiockey Sticks approach is best.
If you actually stop and talk to the person he barks at ask them to ignore him completely and ignor him yourself, other than to keep him quiet. when the attention is not focussed on him and you are chatting and nothing frightening is happening he should relax, also he will realise that his barking is not frightening off the people he is afraid of, whcih is how it looks to him now, he barks and people go away.