Thank you for the response. And thank you for noticing that there has been a lot of research done on this family.
There are many assumptions based on circumstantial evidence. I would be willing to specify why dates are what they are on both Thomas Skinner and Mary his wife. There is very little documentation, but a lot of assumptions on this couple. I have spent a lot of time with the original Chichester (Sussex, England) records as well as the Malden (Massachusetts) records. There are bits and pieces of information that the original Skinner Family Association Group (SFA), organized in the early 1900s, found about this family, but hard records were minimal.
As for the "precise" birth date, birth place, marriage, etc., I did find a mention in the Malden town records where Thomas Skinner self reports his age. I presume the early researchers of the SFA used this town record as the basis for his birth year of 1617. It is believed his family was from the Chichester area (his three children were baptized there). There are indications in the Chichester records that his family was in the area from the mid-1500s, although there is nothing in those records that can verify a family tie. "Just because it looks good, doesn't mean it is."
Some years back, the current Skinner Family Association had Debrett's in England research Thomas Skinner of Malden to see if they could come up with his ancestry as it was thought they had access to more records. Debrett's concluded that there were so many Thomas Skinners born in that time period that they could not come up with any conclusive evidence as to his ancestry or where he came from.
Also, the current Skinner Family Association group is looking for his burial location in Bell Rock Cemetery in Malden, MA. A record from 1969 indicates that his headstone was visible at that time, although various trees have been published indicating that Thomas was buried at Bell Rock, but he was "moved." A lot of research has been done with this issue, and is continuing, both on the burial location of Thomas Skinner as well as Bell Rock Cemetery. (More on that later,)
So, yes, there has been a lot of research done, and there is still a lot more that can be done. However, as with all of us, life gets in the way.