Your care visits should be at set times, if you are having trouble with them ask for different set of carers however if carers turn up at an earlier client and there is a problem they have to wait until the appropriate service arrives to take over.
There is a lot of confusion about the role of Macmillan nurses. They normally do not provide hands on care, they may do a one off to teach a technique to a family carer.
So far as the pain relief is concerned you or your sister need to ask them to explain their rationale, I doubt it was about paperwork more likely it was too close to a previous dose, or they felt it was inappropriate prescribing, as I said in the other place they can only advise and the GP was able to over rule the advice.
In terminal care, taking off PPE is sometimes about connection, but if it was just masks they removed it may be was so they could communicate more easily. They should keep gloves on it they were involved in hygienecare .