Bernard McAlinden in Clonduff Parish on Griffith's valuation was in Ballykeel Townland, on Parcel 23a, house, offices, and land. The parcel didn't change hands until 1877, when the occupier is Owen McAlinden. (Valuation Revision Books)
There are three deaths of Bernard McAlindens in Newry Registration District from 1870 to 1875, any of which could be that Bernard:
from
https://civilrecords.irishgenealogy.ieBERNARD MCALINDON
Date of Death 1870
Group Registration ID N/R
SR District/Reg Area Newry
Deceased Age at Death 60
Returns Year 1870
Returns Quarter 1
Returns Volume No 1
Returns Page No 738
BERNARD MCALINDON in 1875
Group Registration ID N/R
SR District/Reg Area Newry
Deceased Age at Death 74
Returns Year 1875
Returns Quarter 1
Returns Volume No 1
Returns Page No 802
BERNARD MCALINDON in 1871
Group Registration ID N/R
SR District/Reg Area Newry
Deceased Age at Death 78
Returns Year 1871
Returns Quarter 2
Returns Volume No 6
Returns Page No 579
The man who died age 60 in 1870 is a possibility for your Bernard, if his age at death is incorrect, which it usually is. (His son Peter was born in 1826)
But 7 years is a long time for the recordkeeping on the parcel to catch up with a death. It's usually a year or two.
You'd have to pay for the record. It should list the townland of death and informant, which often is a relative.
And, if your Ann Trainer and Bernard McLinden were from Clonduff, he might have died between the Tithe books and Griffiths. Then on Griffith's the land would be in the name of one of their sons who remained in Ireland.
Ann could have arrived in Scotland anytime between the 1861 census and 1871. Or even before 1861 and just not show up on the census. And she might not have left immediately after her husband's death. She might have stayed with her son until she and the children thought she would be better off with her daughter in Scotland.
For the deaths, I searched for just Bernard, no surname, Newry Registration District, 1864 to 1877. There were none that matched before 1870.
I'm just thinking out loud here, you have probably run through all these possibilities yourself.