First, Thomas Welles (or Attewell) of Little Haywood and Hoar Cross was not a son of John Welles, 5th Baron Welles and Eleanor Mowbray. John Welles had no son Thomas. No Thomas occurs in any record; their coats of arms are co,pletely different; Thomas would have been the oldest son and so the 6th Lord Welles; John Welles made several indentures with remainder interests to his heirs spelled out and if he had a son Thomas he would have been named. So, the Welles family you are investigating is completely separate from the Lord Welles line.
Some clues to this family and the connection to the Aston family can be found in:
- See Collections for a History of Staffordshire, Volume 2 (Birmingham: Wm Salt Archaeological Society, 1881): page 132 for clues as to ancestry. ''"History of the Parish of Blymhill:"'' by George Bridgeman.
- Shaw, Stebbing. ''The History and Antiquities of Staffordshire'', vol. 1. (1798): page 104. Need to find free copy
- https://www.geograph.org.uk/photo/4461655
- The Victoria History of the Counties of England: A history of the County of Stafford. Tutbury and Needwood Forest, Volume 10 Snippet view page 309.
"Henry was apparently succeeded by a daughter, Ermintrude, the wife of Adam Aston of Ashmorebrook (in Burntwood, near Lichfield), and in 1431 their son Richard surrendered Hoar Cross to his daughter Alice and her husband John Attewell (or Welles).9 The later descent is uncertain but Thomas Welles, presumably John's son or grandson, was the lord by the late 1480s10. His heir in 1509 was his son John, a Staffordshire MP on various occasions, and John was succeeded in 1528 by his son Humphrey.11 " (unfortunately I can't get the references given to come up in google snippet view so I don't know what references 9, 10, 11 are).
I think it likely that the marriage of Thomas Aston to Cicely Aston is an error - it is too unlikely that father and son both married an Aston.