I'm assuming you've probably got your information from an online tree/trees which I'm afraid is/are wrong especially with regard to John Lovell.
Yes, a John Lovell was bp.8/5/1642 St. Andrew, Holborn, son of Edward (Buttermaker) and Margaret. However, this John Lovell died and was buried the following year!!
John Lovell bur.23/6/1643 St. Andrew, Holborn, son of Edward Lovell, Buttermaker.
So, whoever the John Lovell who married Alice Southin 19/1/1667 St. Bartholomew the Less, London was, he definitely wasn't the one bp.8/5/1642 to Edward and Margaret as that one died as an infant.
(I note from the online trees that both John and Alice's fathers are stated to be named Edward and yet none of their 3 sons bore this name which is very odd for the time).
In fact, looking at the trees I suspect a great deal of the stated facts. I find it very strange, for instance, that the Robert Lovell bp'd 1715 is said to be the only child born to a Robert Lovell and Mary Payne married in 1693, some 22 years after the marriage. Sounds very suspect.
Annette