I'm glad you are getting answers. It seems you are well on your way to solving the puzzle. A child may feel frustrated/angry when they may be missing things which are going on around them if this causes them to feel they can't keep up or are somehow left out.

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Behavioral interventions?
This may seem simplistic, but here are three ideas:

1) When asking her to brush her teeth or feed the fish, have you tried adding an element of body language? Also have you used her name at the beginning of speaking to her, and tried asking her to repeat back to you what she will be doing? Have you tried singing the to-do items? These strategies may help engage other parts of her brain which may help her compensate. This may help her create mental check-lists.

For example, using any melody such as walking up the scales, or twinkle twinkle little star: "(name), time to go and brush your pretty teeth!" Mime toothbrushing. Singing: "Tell me what you're going to do now."

Singing: "(name), time to go and feed our hungry fish!" Mime sprinkling food flakes. "Tell me what you're going to do now."

She may learn to sing or hum to herself to keep focused on a task and stay on track to completion. This may help her screen out other thoughts which may compete for her attention.

2) Another idea may be to gently ask her what she is thinking about, if you see she is drifting or has a far away look in her eyes. This may help her develop an awareness of her thoughts, possibly a step to controlling those thoughts and setting them aside to attend to matters of interacting with other people and completing to-do items such as turning in homework.

3) Because you mentioned she likes to write and draw, might she be interested to write and draw stories of her successes and foibles? This may help raise her awareness and also her ability to laugh at and accept the funny things like showering with socks on (my guess is that her feet felt cold to her and therefore already seemed to not have socks on). This may tie into asking her what she was thinking, not in a judgmental or disappointed way, but in a way that indicates there must've been a good reason, and encouraging her to take time and reflect on what she was doing (re-enactment can help with this, stepping through each action with her and seeing what she did and what her thoughts were at the time). Being able to successfully self-reflect and report may be helpful. Writing and illustrating her own book, possibly with thought bubbles, may be one way to do this.

Best wishes to you and this precious child.