Out of the GWENNAP FRYING PAN and straight into the ST IVES FIRE.
I agree that Gwennap is getting a little difficult to handle just now.
I have found 19 Quick marriages from 1754 to 1833 that need to be traced and many of those were females.
(In fact only three of these marriages were for Quick men.)
Righto - I will deal with your queries in reverse order.
I have absolutely no idea on this one just now and do not have any of them in my database.
Can also find no trace of a marriage for James and Jane in the IGI so will have to start searching through all my Marriage records to see if I can find something.
Once again I am currently unable to help you with James although it is certainly possible that he was son of Richard.
But there is one little spanner that has been jamming up the works on this bloke.
James gave his occupation as
MASON when he married Ann Tonkyn in 1780.
BUT:-
James QUICK,
MASON, married Martha PEARCE 29th April 1781 at St Ives and had children James, Martha, Ann, Elizabeth and Mary.
I am not really sure right now just how to determine which of these two belongs where.
The only thing we do know is that they are two separate individuals given they were both having children at the same time.
And now I suggest you get yourself a nice, big and very clean Drawing Board and plenty to write with.
To my knowledge none of the above children belong to this particular James and Mary Quick.
Here is the scenario as I have it:-
(I will begin with Mary as she was married first)
Mary QUICK bp. 22nd September 1752 at Zennor d/o John and Wilmot.
Married 26th December 1775 at Zennor
John QUICK bp. 31st December 1749 at Zennor s/o Thomas and Elizabeth (nee STEVENS).
One child - Mary bp. 5th January 1777 and bu. 4th August 1780 at Zennor.
John QUICK bu. Zennor 5th January 1777.
James QUICK bp. 26th December 1750 at St Ives s/o James and Catherine (nee TREWHELA).
Married 3rd April 1778 at Zennor
Mary QUICK, widow.
Children:-
John bp. 9th May 1779 and bu. 21st August 1780 at Zennor
John bp. 15th July 1781 and bu. 6th September 1781 at Zennor
John bp. 8th July 1782 at Zennor (m. Mary USTICK 23rd December 1811 at Morvah)
James bp. 25th June 1786 and bu. 29th April 1788 at Zennor
James Thomas bp. 25th January 1789 at Zennor (m. Mary COCK 11th January 1817 at St Levan)
Dionysius bp. 11th July 1790 and bu. 30th August 1790 at Zennor
Mary Ann Eve bp. 30th October 1791 at Zennor
Mary QUICK buried 18th May 1798 at Zennor.
James QUICK (not listed as a widower!)
Married 26th October 1799 at Zennor
Dinah RICHARDS bp. 26th December 1771 at Zennor d/o William and Alice (nee BERRYMAN)
Children:-
Elizabeth bp. 17th August 1800 and bu. 3rd November 1809 at Zennor
Dinah bp. 25th December 1801 at Zennor (m. John CHAPPLE 14th July 1828 at Zennor)
William bp. 20th July 1805 at Zennor
Matthew bp. 7th February 1808 at Zennor (m. Alice NANKERVIS about 1836 at Zennor)
Thomas bp. 12th August 1810 at Zennor (m. Maria MICHELL 1st August 1835 at Zennor - bp. 20th November 1814 at Zennor d/o Samuel and Mary (nee TREWHELLA))
Elizabeth bp. 10th November 1816 at Zennor (m. John DALE after 1834)
James QUICK was buried at Zennor 22nd Apri 1823 age 73
That is the scenario as it was worked out over the last ten years.
The above means that James was 65 when his last child was baptised which is most unusual but certainly not impossible.
It also means that I need to go through the whole thing again very carefully but it is, as far as I know, pretty much correct.
A final note about your 'now orphaned' children of James and Mary:-
The only other possible marriage I can find at the moment (from IGI) is this:-
James QUICK m. Mary HUMPHRIES 18th November 1774 at Falmouth
The IGI lists only two QUICK children baptised at Falmouth - John (1802) and Mary (1804), both children of John and Mary.
A look at the Falmouth Marriage Register would be very handy here and it is unfortunate that I have been unable to find the Phillimore & Taylor Transcript for Falmouth on the Internet.
Found plenty of others but not that one.
It is very possible that the above Marriage is that of the parents of Francis & co.
Best I leave it at that for now as you will be tearing your hair out I should think.