For the conversion into the Non Immigrant O visa there is NO seasoning of the money required.
For application of the 1 year Extension of Stay the money must be at least 2 months in a Thai bank account.
As the are named the same, retirement visa, the conversion into a visa and later an application for 1 year Extension of Stay are two total different ways of stay with different rules, regulations and requirements.
There is no official limit on how many times a person can apply for a visa.
Neighbor countries did stamp visa in the past that the person does not get another tourist visa at that Embassy after 4 or more back to back visa applications.
Get a visa that fits your purpose of living inside Thailand, do not use the short term tourist visa options.
NO, as a stay based on visa exempt entry, 30 day Extension of Stay based on tourism and conversion into a Non Immigrant Visa do not count forwards in the rules of 90 day reporting.