I am particularly interested in his connections to the Howgill family (and particular the Quaker Francis Howgill, who married second a Mary ...). He is not the same as the elder Robert Hebblethwaite who was the first head of Sedbergh School and also in holy orders.

Heblethwait is noted in Alumni Cantabrigiens, and, per Miscellanea Genealogica et Heraldica, 3rd series, vol. II, page 17, was descended from ancestor James, and was a cousin to Henry, the citizen and draper of London. Refer to your pedigree 1431. Of course "cousin" can be applied quite loosely to describe such a relationship.

Per Robert's 1626 Will, he mentions his sister Mary Howgill of Kendall, Westmoreland, and references other relations in Sedbergh.