taf, Thank you, as always, for all points and insight. I must be making a bit of progress (!); one of your points occurred to me ["It is the mention of Joan at all, rather than just namig Cuthbert, that suggests the connection - genealogical or social - involved her."].
I may not have wondered about a family relationship here had I not also found some other Revell/Langton/FitzRandolph connections -- an ancient deed in which Christopher FitzRandolph and wife Joan Langton (Cuthbert's daughter) grant land to a Roland Revell (very possibly the son Roland cited in Hugh's will); a suit Cuthbert brought against Randall Revell, likely the bastard son mentioned in Hugh's will; another suit brought by Cuthbert against Christopher Fitz and Roland Revell; and a suit Cuthbert brought against Christopher and wife Joan (his daughter) concerning, in part, I think, lands the pair had granted to Roland Revell. Together, could these things suggest a connection (especially since both Roland and his half-brother Randall are involved at various times)?
Question related to land grant to Roland: I assume that "grant" means "give," and not "sell?" The couple granted the lands to Roland reserving the right to buy them back if/when any of the couple's children reached majority:
"Indenture, dated 20 September, 10 Henry VIII, witnessing that Christopher Fitzrandolf of Codnore and Jane his wife, daughter and one of the heirs of Cuthbert Langtone of Langton Hall, have granted to Roland Revell of Maunsfeld, all their lands, etc. in Hukenall under Hucthwet alias Dirti Hukenall, near Sutton in Aschefeld, with liberty to buy them back for 8l. 6s. 8d. on the coming of age of any heir of their bodies. English. Endorsed, Inter Revell et Fitzrandall for lond in Mancefeld."
I don't yet know the many conditions under and purposes for which people granted land, and whether the buyback provision could signal that the lands may have belonged to an ancestor of the childrens'...possibly Hugh Revell? That maybe these are lands brought to Cuthbert's marriage by his wife, who could have been Hugh's bastard daughter/Roland's half-sister? (But as you pointed out, if this were the case, would Cuthbert likely have served as his contracted wife's guardian, rather than someone else?)
In any case, is it significant here that Christopher's wife Jane is identified specifically in the indenture as an heir of Cuthbert? Does this reference likely indicate that granted lands came from her family and not Christopher's?