If your child is having a valid Qatari Residence Permit (Visa) stamped on your child passport and you are returning before the date of expiry of passport, there are no issues to enter the country.

Electronic passport is not required for umrah as of now, Saudi has extended this rule. Hand written passport is acceptable.

If Umrah visa already issued, there is nothing to worry.
Include us in your dua when you travel.
May Allah bless you with safe and beneficial journey.

Any issues please do not hesitate to contact.