You are going to struggle looking for Jones' in Wales without more information!
The Hindoo sailed from Caernarfon to New York, arriving on 28 May 1842, and looking at the group of Jones' you have identified:
142 William Jones 25 Quarryman [born c1817]
143 Robt Jones 30 Labourer [born c1812]
144 Evan Jones 19 Labourer [born c1823]
145 Owen Jones 21 Labourer [born c1821]
146 John Jones 24 Labourer [born c1818]
147 Griffith Jones 21 Labourer [born c1821]
1. The occupation of "Quarryman" usually points to the north-west of the country, as the majority of the slate quarries were in Caernarfonshire or Merionethshire. This would also fit in with a departure from the town of Caernarfon.
Of course there is the possibility of stone, rather than slate quarrying, and this might fit in with Cefn Mawr.
But I believe there was no real quarrying industry in the south of the country, which might rule out Llandeilo, Mountain Ash, Merthyr Tydfil and Rhydfelin?
Where did you get all of these variations?
2. As they emigrated in 1842 they should all appear in the 1841 Wales census. Unless they were from Cefn Mawr! The entire Ruabon census for 1841 is a "lost" census, so you will get no further in this case.
3. The passenger list does not include anyone with the surname Miles or Webb.
4. The name Mary Sion is dubious. "Sion" is not a Welsh surname but is possibly a patronymic? "Sion" is just the Welsh version of "John", so I would suggest she was simply "Mary John" or "Mary Jones"?
5. In the notes attached to your Ancestry tree you have "They landed at New Orleans, LA and went up the Mississippi by steamboat to Galena, Illinois", but the Hindoo sailed to New York? How did they get to New Orleans?