For Question 2. It will be easier if your husband will have your son’s birth certificate (PSA with an APOSTILLE because Philippine Embassy is not accepting documents with red ribbon anymore unless the document with red ribbon has already been previously authenticated by the embassy. After having it authenticated in Philippine Embassy in Doha, he needs to bring the document to Qatar-MOFA.
For Question 3. Return ticket should be dated 30 days starting from the day your husband applies for your son’s visa.
For Question 4. Yes, you need to have it stamped using wwwexpress in the Philippines. You can visit their website to know the requirement and fees. Your requirements will fall under the category 2 which is Personal /Official / Government Visa and NOT under category 3.
For Question 1. You need to bring the printed visa and Qatar travel insurance (needed in Airline’s check-in counter). BTW, both of you are entitled to a reduced travel tax which means you will be paying only P300 for each of you instead of paying P1620 Travel tax each(P2640 discount for both). So when paying for your travel tax in the airport be sure to inform the Travel Tax counter that you will avail for the Reduced Travel Tax. (Documents needed for RTT are the ff: husband’s OEC and passport copy, you and your son’s passports, Marriage certificate with an Apostille, son’s birth certificate with an Apostille and flight tickets). You need to present to Philippine Immigration your passports, boarding passes and an honest answer from a wife who has no intention of working but only to be reunited with her husband along with their son. Just answer them only of what they ask.
GOOD LUCK.