I can't answer them all obviously, but:
If he thought that there was someone in the toilet why not grab his gun and hit the panic button?
Is there aactually panic button?
Then with his gun trained on the area where he heard a noise shout a warning that he was armed?
He did shout out, not sure if he said "I have a gun" that hasn't been made clear
This could have easily happened and he could have then exited the room or protected Ms Steenkamp with the weapon whilst awaiting for the armed security guards that were in abundance on the estate.
The bedroom door was locked and don't forget he can't get downstairs without his prosthetic legs on
Or she could have said, 'Baba I'm in the toilet'
Not if she thought the intruders were coming in from, say, the balcony
He was a trained shooter. From the group on the door - in the dark?- he was more than capable of protecting himself and Ms Steenkamp.
Not if there was more than one person perhaps
Why would Ms Steenkamp go to the toilet in pitch darkness?
They were both awake.
Dunno
Why is there a spray of blood above his bed?
Arterial spurting. This was explained very early on in the trial