Mum has been very specific about her wishes ....not just 1 place but 2 for the scattering of her ashes. Her 2 favourite places when walking the dogs in the Quantocks.
She even managed to buy a coffin ( wicker thing) and store it in her sisters loft , and didn't tell my stepdad as she didn't want to alarm him. You should have heard him retelling this to the undertaker....." Oh yes, we already have a coffin, don't know what it looks like though , where it was bought from or anything else. She was a bloody stubborn woman "

Difficulty is she had asked for some specific travel arrangements but changed her mind a few weeks ago....and now some of the stirrers are saying that she was bullied into this when she was unwell and not knowing what she was saying. FFS she knew what she was saying right up to the end.
I have seen such problems before. My belief is that the 'interefering' parties are doing it from a sense of guilt that they did not do enough when your Mum was still alive.
It is for their peace of mind, not yours, or memory of your Mum.
Firmly tell them that you are next of kin, you are making the arrangements and that Mum would be very upset by all their squabbling and interference.
Sadly, it will be similar when the distribution of sentimental items happens later.
You are a sensible woman and the "bloody stubborn" force is strong in you as well.
You can and will cope admirably.