I think it has been resolved for now. Kanyakumari passenger associations and a few south TN MPs have been demanding Charminar Extension for more than 2 years now. They'll probably try again now that doubling works are complete and NCJ/CAPE has additional infrastructure.

SCR would not be interested in this because it will bring down the quota of existing SCR stations. They would also need to allocate a 3rd rake for this.
Not...
more...

feasible unless SR perhaps takes over the train and Primary Maintenance.

So many alternatives available for SR. They could increase the frequency of NCJ KCG or introduce a new train altogether if you want it via GNT/BZA.

Possible to introduce a train from MDU to HYB in RSA with Amritha Exp such that it reaches HYB around noon and departs around 3 pm the same day.

And there's no point routing such trains from through Chennai, otherwise it effectively becomes 2 trains in practice (Daytime Intercity between down south and Chennai).