OK, a few points to cover:
Bootle church records & census returns are available at Liverpool Record Office at central library. I do have the 1841 index for North Liverpool which includes ages and occupations.
I'm afraid I only have Christ Church baptisms 1821-1838, I'm not sure what else is readily available (I'm not aware of any printed transcripts for sale for other events/years).. but Southport Library may have the records on film or their own transcripts.
Here's Michael Formby's 1851 return at Snuttering Lane 498/27:
Michael Formby. head. 29. Bricklayer's Lab. Formby
Alice Formby. Wife. 28. Formby
Elizabeth Formby. Dau. 6. Birkdale
John Formby. son. 5. Southport
Ann Formby. Sister. 20. Hse Serv. Formby
There is just one other Formby in the North Meols census. Manchester Rd 470/86:
Ann Formby. Head. 73. House Proprietor. Liverpool
Jane Naele. grand daughter. 16. Kirkdale
Emma Yates. Vis. 61. Sick Nurse. Bolton
Now for the other Croppers in the town:
544/21. Churchtown
John Cropper. Head. 47. Cotton Weaver (rtd). North Meols
Richard Cropper. son. 18. Handloom weaver (silk). N Meols
Ellen Cropper. Dau. 15. Handloom weaver (silk). N Meols
525/16. Rowe Lane
Richard Cropper. serv. 19. N Meols. Ag Lab for farmer, Henery Rimmer, aged 34)
575/40. Marshside
Richard Cropper. Head. 76. Ag Lab/Pauper. N Meols
Alice Cropper. Wife. 79. Pauper. N Meols
610/98. Crossens
John Waring. Head. 55. Farmer. Scarisbrick
Ellen Waring. Wife. 51. Scarisbrick
James Waring. son. 26. N Meols
John Waring. son. 24. N Meols
Alice Waring. Dau. 22. N Meols
Thomas Waring. Son. 19. N Meols
John Waring. G/son. 6. At Home. N Meols
Henry Cropper. G/son. 5. At Home. N Meols
Betty Waring G/Dau. 2. N Meols
630/3. Gor Hall, Gorsey Lane
Thomas Cropper. Head. 48. Farmer. N Meols
Elizabeth Cropper. Wife. 52. N Meols
Ann Cropper. Dau. 18. Employed at Home. N Meols
Ellen Cropper. Dau. 13. Dressmaker. N Meols
Richard Cropper. Son. 9. Scholar. N Meols
Isabel Cropper. Dau. 5. N Meols
plus servants Thomas Brookfield 18 & Peter Prescot 16, both born N Meols
638/56. Charnleys Lane, Banks
Peter Cropper. Head. 80. Farmer. N Meols
Ann Cropper. Wife. 75. N Meols
Margaret Cropper. Dau. 49. N Meols
Isabel Cropper. Dau. 32. N Meols
Peter Cropper. Son. 30. N Meols
Hamlet Cropper. son. 26. N Meols
Hugh Waring. Serv. 17. N Meols
Note Hugh Waring, same name as the grandparents of Henry Cropper... perhaps Hugh is a relative.
These, plus those you have already, are the total Croppers in North Meols in 51, there were none in Birkdale. Obviously, there are many Formbys in the Birkdale, Ainsdale, Formby & Altcar return, but I'd need a guide for who to look for if you need details of Michael's family.
Though the idea of the couple marrying in West Derby is odd, given their origin and residence in 1871 being North Meols... it does seem a remarkable coincidence if the father was named as Michael.... this wasn't a common name in the 19thC.
One thing that should be noted, though, is that if they did marry in West Derby, they would require a local residence to fulfill the legal requirements for the marriage. It was common, therefore, for couples to take a temporary residence or just give a friend's/relative's address as their own in order to give the impression of living locally.
If family disapproved of the match, or they felt that someone may make a formal, legal objection to the marriage, they may have chosen an area where no-one knew them. Was one of them under 18? if so, they may have gone to another area and lied about the age because the parents wouldn't give the necessary consent (as was, and still is, required for a marriage for someone aged 16-18).
Let me know how you get on with that lot
Impy