I have not had much time to delve deeply into this and my information is now based on work from 2011, 2015 and 2021.
From what I was able to work out back then the scenario's are:-
1. Zenobia Stevens bp. 25th March 1764 Zennor to William Stevens and Margaret nee Berriman - she is the one I believe married Mark Daniel in 1785 at Zennor.
Zenobia Daniel was buried at Zennor 15th September 1850 with her age recorded as 58 which is midway between the baptisms of the two Zenobias.
Children from this family:-
1. William 1785 Zennor married Jael Man at Zennor in 1815
2. Mark 1787 Gulval married Alice Daniel at Morvah in 1811
3. Matthew 1790 Zennor married Judith Newton at Zennor in 1819
4. Henry 1792 Zennor married Mary Ann Uren at St Just in 1815
5. Zenobia 1793 Zennor married first David Eddy at Zennor in 1813 then second William Renoden at St Ives in 1826 ('Sinobia' Renowden died in Hampshire in 1861)
6. Thomas 1795-1802 Zennor
7. John 1798 Zennor
8. Elizabeth 1800-1802 Zennor
9. Elizabeth 1803 Zennor married Nicholas Stevens at Zennor in 1830
2. Zenobia Stevens bp. 2nd April 1761 Zennor to Vivian Stevens and Margaret Phillips married Richard Berryman at Zennor in 1779. She was buried at Zennor in 1838 age 77.
Children from this family:-
1. Job 1781 Zennor married Sarah Brooking at Zennor in 1808
2. Thomas 1783 Zennor married John Jelbart at Zennor in 1809
3. William 1784 Zennor married Jennifer Eddy at Gulval in 1810
4. Elizabeth 1785 Zennor married John Berryman at Towednack in 1807
5. Richard 1788 Zennor married Jane Richards at Zennor in 1815
This last family was last updated in 2011 and 2016 so parts are still a work in progress and need to be reviewed. But as an overall scenario I am currently quite comfortable with my conclusions.
Hopefully that will help solve part of your problem at least and also relieve some of the pressure in the old noggin!
This family may be the other way around.
As I have DNA results (including confirmed family members) to my line of Zenobia Stevens and Mark Daniel (My 5X great grandparents) Confirms that this Zenobia is the daughter of Vivian Stevens and Margaret Phillips.
The second Zenobia is the daughter of William and Margaret Berriman it shows my DNA matches as a removed cousin via her marriage to Richard Berryman in 1779, she dies in 1838 Porthmeer.
This Zenobia is a cousin to my Zenobia. No wonder people are getting muddled with them all.
I believe the birth dates have thrown many, and the death dates don't give correct ages.
Hope this is of some help for those looking.