Sorry, but waiting times at Immigration Office is not that visa related.
To avoid waiting there is an on-line appointment system, if you did not use it you wait until the persons why arrived before you are served. It takes as long as it takes.
NO, you first apply for a conversion of your Tourist Visa into a Non Immigrant O visa based on being over 50 years of age (retirement visa) and for this you need proof of 800.000 Thb being send into a Thai bank account on your name from abroad. No seasoning needed for conversion.
If you have this new visa you also get 90 days permitted to stay, after 60 days you can apply for the 1 year Extension of Stay based on being over 50 years of age (retirement visa, yes same same but different) and then the money is already more than 2 months into your bank account if you did not take it out for other reasons.
You may need a Certificate of Residence from Immigration to open a bank account.
You can only apply for a conversion into a Non Immigrant O visa when you meet all the requirements. Get a Certificate of Residence and the hand out with requirements to apply for a conversion from the Phuket Immigration Office, open a bank account, deposit the money, get the bank letters and tick the list with other requirements before going back to Immigration.
With a Chinese passport you can enter using the 15 day Visa on Arrival which you have to buy on-line before travel or directly on the airport after landing.
You can not validate the Non Immigrant IB visa inside Thailand, therefor you have to leave the country and enter again using the visa.
So you entered with a 30 day Visa Exempt Entry and already got the 30 day Extension of Stay based on Tourism.
1. NO, you can only extend a visa exempt entry once with another 30 days based on toursim.
2. Yes, you can always apply for the Extension of Stay based on being unable to travel, but to issue this is the decision of the Immigration Officer.
When your application is not approved you get 7 days to leave the country from the day of application or if the Immigration Officer is lenient he might give these 7 days from your last day of current stay.