Most of what you said is true.
Under understanding and talking you want to do a call a response with him when it comes to learning numbers.
Make it fun. Use flash cards. When you say the number one. point to it on the card so he can say it also.
Do the same for the alphabets.
When he is being washed and dressed name body parts and have him repeat it. He will learn his left and right this way, because it will be told to him every day while he is being washed and dressed.
Make it fun. Make up a song.
I know it may sound crazy, but that is how I taught my nieces, nephews and son. I started this over twenty years ago. My son is seven years old.
Also he can learn his basic colors. Do it once daily. Again, make it fun.
I hope this helped.