no, the age of the person has no relavance to their eligibility for OHIP. Visitors are no eligible for OHIP. A PR applicant is not eligible for OHIP unless they have received AIP as part of the inland process. Children are not eligible for inland, therefore they would not be eligible to receive OHIP under that rule.
The Service Ontario website has all the information about eligibility requirements, so i suggest doing some reading there. See below:
http://www.health.gov.on.ca/en/public/programs/ohip/ohipfaq_mn.aspx
You may be eligible for the Ontario Health Insurance Plan (OHIP) if you are included under one of the following categories:
you are a Canadian citizen, permanent resident, landed immigrant or are registered as an Indian under the Indian Act;
you have submitted an application for permanent residence in Canada, and Citizenship and Immigration Canada has confirmed that you meet the eligibility requirements to apply for permanent residence in Canada;
you have applied for a grant of citizenship under section 5.1 of the Citizenship Act (Canada), and Citizenship and Immigration Canada has confirmed that you meet the eligibility requirements to apply for citizenship (i.e. children adopted internationally by Canadian citizens);
you are a “protected person” – i.e. a Convention Refugee or a person in need of protection as referred to in the Immigration and Refugee Protection Act;
you are a foreign worker who holds a work permit valid for at least 6-months which permits you to work in Canada, and you are working under a formal agreement in place to work full-time for an employer situated in Ontario which sets out the employer’s name, your occupation, and states that you will be working for no less than six consecutive months;
you are a foreign clergy member who will be providing services to a religious congregation in Ontario for at least six months;
you hold a Temporary Resident Permit with case type 80 (for adoption only), 86, 87, 88, 89, 90, 91, 92, 93, 94 or 95;
you are the spouse, same sex partner, or dependent child (under 22 years old or 22 years and over if dependent due to a mental or physical disability) of an OHIP-eligible foreign clergy member or OHIP-eligible foreign worker;
you hold a valid work permit under the federal Live-in Caregiver Program;
you hold a valid work permit under the federal Seasonal Agricultural Worker Program;
AND, generally speaking
you make your primary place of residence in Ontario;
you are in Ontario for at least 153 days of the first 183 days immediately following the date you establish residence in Ontario (you cannot be absent for more than 30 days during the first 6 months of residence);
you are in Ontario for at least 153 days in any 12-month period.
Tourists, transients or visitors are not eligible for OHIP coverage.
