PIP AND PREMIUMS

My husband receives ESA CB - £110.75 pw. Recently awarded PIP enhanced daily living and enhanced mobility due to a terminal cancer diagnosis. I was on ESA IR but was living apart from my husband who is now living with me. DWP wrote to me to say my ESA is now CB - due to taking into consideration my husband's income and no longer IR - we are BOTH in the SG of ESA. My question is - is he entitled to any extra premiums which should be added to his ESA CB? If so, would this mean some of the CB would be considered Income related and therefore help with housing benefit and council tax reduction? He also receives IIDB of £69 per week.
Should LHA provide me with a 25% reduction in council tax as my spouse receives the daily living component?

Is EDP only paid if you receive ESA IR? Thought it was applicable if you got higher rate of PIP?

Do you think the change in my circumstances will mean an amendment only to my existing claim for Housing Benefit or do you think it will trigger a new claim for Universal Credit?