Validation are only issued by GCAA after obtaining your residence visa
Not exactly correct. I had a letter of validation about 5 months before I had the residence visa. They will not issuse the permanent certificate until you have a visa.
To my knowledge, you do no need to have any time in type for license validation. I had Zero time in type and it was not an issue but then again my/our training was done in the States by a GCAA approved school and instructors.