Usufructuary Mortgage limitation and Tenancy?

Namaste, Can soneone please assist on below query.
A land was usufructuary mortgaged in 1928 for 6 years by Mr X to my Mr Y with possession towards interest.

Mr X died in 1968 without redeeming,

Mortgagee Y LET out property to Tenants under Karnataka Land reforms act in 1982. Mortgagee stood EXPARTE in that Land Tribunal case. Mortgager and his legal heirs were UNAWARE of this facts.

Can the Legal Hier now in 2015 claim for redemption of usufructuary mortgage property. If YES, what is the effect of TENANTS? Can Tenant be EVICTED from Mortgage land on Redemption?

we looked into the judgement given by Supreme Court ie., http://indiankanoon.org/doc/116608229/ "Singh Ram (D) Tr.Lr vs Sheo Ram & Ors on 21 August, 2014",
Can Usufructuary Mortgage done with a time limit is also entitled to be redeemed after 30 years? Or it applies only for Usufructuary without time limit?
Namaste

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