Practical answers for you to consider;
1. If Tower CTR is inactive (MBZ) then CTA does not exist so lower limit is as per DME/GPS arrival steps.
2. If NDB is the azimuth aid being used you must have the ident monitored as you have no other means of detecting a failure of the aid. If VOR as azimuth aid, you have the fail flag so ident need not be monitored, but you can if you wish I suppose.
Cheers,
Zhaadum
