Hello Louise, welcome to Rootschat

You haven't stated on what dates the two baptisms for Thomas took place. The date of birth on the second one may just be an error for some reason. If you have the same parents and dad has the same or similar occupation then it is probably the same child. For whatever reason the parents had Thomas baptised twice. Families can do strange things sometimes.
I wouldn't worry too much about Vallins/Vollins. Spellings can quite often be different due to what was heard. It's a hazard of family history. Names get misheard and spelt differently.
The 1841 census has the Packman family living at Reynolds Smith, St Mary Cray, Bromley, Kent and it appears that Amy's dad is with them. Listed as John Vallins. Looks as though James's occupation is shop man.
Did you check to see if Amy had any siblings? If so the parents should be consistent even if the spelling of the surname varies.
If you are looking at family trees on Ancestry you need to take some of them with a pinch of salt. Regrettably there are researchers who just lift names from other trees and copy them without checking to see if they are correct. The golden rule is do your own research and check what you find against parish, census and BMD records where possible.
Is there anything else you would like help with? Rootschatters are always willing to assist others in their research.