Sorry for the delay in replying. William Rickward was illegitimate and I just haven't been able to get any further with him.
Ann Hall who was a visitor with him in 1851 from Shropshire age 84, well I thought she may have been his mother (right age) looked for a death and even got one death cert (wrong one). You do have the details of those who went to America I think. If not contact me via e-mail (still same e.mail ad).
Happy New Year