I see 4 Robinson households farming in Roughan in 1828, according to the tithe applotment records:
There were 2 Hewitts farming in Mulladry:
Going forward to Griffiths Valuation for Roughan (1864), a Henry Robinson is listed on plot 4 which was just under 6 acres. There were 2 other Robinsons in the townland who may be related. Henry’s farm today is on the modern Drumanphy Rd. It still looks to be farmland (judging by Google Earth) but the farm house is long gone.
Henry was deleted in 1866 and replaced by Henry Lappin. I don’t see a death for him then so it isn’t clear what happened to him. Nor can I find a definite death for Jane. There was another Henry & Jane Robinson couple in Griffiths living some miles away in Corbracky. That Jane died 10.1.1888 and Henry in 1893 but as far as I can see it must be a different couple who just happened to share the same (common) names and to have been of similar ages (that Henry is listed in Corbracky at the same time your Henry was in Roughan:
There are about 40 trees on Ancestry which show the family. Most seems to repeat the same information so presumably mostly come from the one source, as is often the case. Henry is shown as born 24.11.1802 to parents James & Margery. Jane Hewitt is shown as born 1806. None of the trees has any information on Henry & Jane’s deaths or of any other children.
Have you searched Drumcree Church of Ireland records for the family? (There’s a copy in PRONI and they might be on the rootsireland site).
There were several Hewitt households in Mulladry in the 1901 & 1911 censuses.
Some were Church of Ireland, 1 Methodist and 1 Quaker family.
Probate of the Will of Anne Hewitt late of Mulladry County Armagh Spinster who died 18 March 1921 at Toberhewney said County granted at Belfast to Reverend Henry McConnell Clerk Effects £1
There was a Hewitt family there in the 1960s, and perhaps beyond:
Hewitt, Alfred James of Mulladry Portadown county Armagh farmer died 13 June 1966 Probate Belfast 19 January to Thomas Alexander and Stanley Alexander farmers. Effects £4900 3s.