The marriage of William and Emily was in the Oct-Nov-Dec quarter of 1853 in Royston RD (Vol 3a Page 301). Royston straddles the border between Hertfordshire and Cambridgeshire, but Ancestry only offers Herts as the county for the RD. The moral of the story is that when searching Ancestry (or any other online source), Less is More. Always best not to refine a search any more than you need to in order to keep the results down to a manageable number. Whatever Ancestry might say, adding extra information does not produce "better" results! Actually, one is almost always better off using FreeBMD for civil registration events. The data is the same, but FreeBMD's search facility is superior.

The marriage certificate (£9.25 via www.gro.gov.uk, including postage) should show Emily's father's name and occupation.

Sorry, but can't help with the immigration side of things.