Referee and picture requirements for child British citizenship

Hi!
I am applying for British citizenship for my child.
I have 2 questions.
1. Referee. I found out that "If the application is for a child, one referee should be a professional who has
engaged with the child in a professional capacity, such as a teacher, health visitor, social worker ".
My son will be 5 years old in May. When he was 3 he started school but has been attending school only for about 2,5 months. Then he had some issues and didn't want to go there anymore. We decided not to force him and let him start school when he'll be 5.
My question is - can I use references from his previous teacher if he was in school only for 2,5 months? and it was more then year ago?
2. We did my son a picture in photobooth because everything is closed. It says it's not suitable for toddlers but we didn't have a choice. Unfortunately the machine said that the photo is blurred (even though my son was sitting still, we did 10 trials) and it didn't pass their requirements. The picture looks fine, normal too me but I don't know if it will be accepted in the application.
Is that possible that my application will be refused because this picture is blurred?