Business
1. What is the process of registering a new startup or open a business in India for OCI holders?
Most probably none!
2. Are there any privileges on loan or taxes or anything else in this regard?
Most probably none!
3. Difference in loan rates for Indians and foreign nationals, for buying properties, apartments, cars, education loan etc.
Most probably none!
4. Any additional expenses need to be borne in case I am Canadian citizen (OCI holder) for running a start-up.
Most probably none!
Pension
1. Since I have worked in Canada for 8 years and would also work in future for few years, would I be eligible to get Pension from Canada if I retire in India ? As a Canadian citizen holding OCI
Most probably, yes
Job
1. For international markets like Singapore or Dubai, do Canadian citizens get any preference over Indian in terms of job or salary?
No that I am aware of, except that Canadian citizenship will help reach International markets faster as you don't need visa to enter...
2. If I am employed with an Indian based firm, would there be any preference for onsite assignments as a Canadian citizen or Indian?
If the project is in Canada or US, may be! Don't count on it...
Dependent
1. If father applies for Canadian citizenship after birth of child, is it mandatory to put child's name also in the application? Can the child remain Indian when parents are Canadian.
No
a. During surrender of Indian citizenship, does the child also has to surrender his/her citizenship?
Yes if the child acquires Canadian citizenship
2. Let's say parents and child all are Canadians and after 5 years if one parent become Indian citizen then can Child become Indian or would it depend on both parents citizenship.
Child does not automatically become Indian, the process has to be followed
3. If one parent has to travel on Canadian passport to other country for work , if child is Indian, can he/she also get visa even being on Indian passport.
Yes
4. If both parents are Canadian and child born in India then can we apply for OCI for a child from India and how soon it needs to be renewed. What about OCI fees.
Yes, if Child becomes Canadian, you can apply for OCI, there is no fee waiver as far as I know...
5. How easy is to get abroad visa for a kid on Indian passport. Any on arrival or no visa countries?
The usual easiness
6. Is the child evaluated based on citizenship of both parents or his own?
At least one of the parents
7. If I continue to hold my Indian citizenship and travel to Germany or Dubai in future, can I make my wife as a dependent given she is Canadian? Any challenges?
Yes for dependent, no for challenges, the consulate might ask a question or two...
8. Can I go abroad on Indian passport and make my wife dependent to me when she holds Canadian passport. ?
You marital status has nothing to do with citizenship
Retirement
1. If I become Canadian citizen and leave Canada after few years forever, are there any formalities I need to do before leaving? Like inform government, any taxes, health or employment insurance etc?
You might have to file tax returns, no to everything else...
2. For what all purposes is Passport mandatory in India?
Nothing, PAN and Adhar are the sought documents...
3. What all are the formalities need to be completed in Canada when I declare that i will be staying in India for next 30 years.
If you are PR, you might lose it. If you are citizen, nothing
4. Do I need to pay any hidden charges for anything in Canada if I leave for India after getting Canadian citizenship? Such as health insurance, job insurance , education or when I am away from Canada.
Only tax man is interested in you, others don't care...
Foot note:
If you think 30 years into future & worry about 200 things that can possibly go wrong, you better cling to your Indian citizenship