I would concur that the merge should be made of these profiles as they're all three clearly the same person. Blix-56 has chunks of text wholesale copied from Marc Hernelind's website, which suffers from a number of problems, not the least of which is the author's severe linguistic limitation (which, of course, he can't help, but it makes for very difficult reading and impossible for automated translation). Månsson_Blix-2 lists nothing, but based on name, dates, and location, is the same as Blix-56.
Hernelid relies entirely, it would seem, on Rygh's 1961 article in Norsk Slektshistorisk Tidskrift, vol. 18, pp. 143-147 (available to buy from genealogi.no). I can save you the $25. Hernelind also, inexplicably, copies out the entire contents of some of the charters cited by Rygh.
Rygh's article is highly speculative, and it appears that the "certainties" reported in the WikiTree profiles attached to Jon Månsson and on Hernelind's website should be considered highly uncertain. Rygh makes this clear, however, and so it appears we have a classic case of things having been copied out of a pedigree without paying attention to the prolific ? peppered throughout.
Looking at the details in Rygh, Joan i Angestad (in the profiles here mistakenly called Jon or John (Månsson) (Blix) is not recorded with neither patronymic nor additional names. He is mentioned, according to Rygh, between 1418 and 1441. In Diplomatarium Norvegicum (hereinafter "DN") vol. XIV, p. 36 here it is made clear that Joan is married to a daughter of a man called Guze, and has a mother-in-law whose name is Eline. Rygh guesses ["...men det kunne kanskje være den Gutzorm i Aghnahal..."] that this may be Gutzorm of Aghnahal , who's known from DN XVI, pp. 59-61. There is no evidence that Joan of Angestad is the son of Magnus Blixe.
It is likely that Guttorm, (known 1483 and d. before 1494) OR his wife was the child of Joan at Angestad, and that either Guttorm OR his wife was the child of Olof at Angestad, as the property was united in Guttorm's children's property. However, the exact relationships are not known, so we cannot say with any certainty that Guttorm was the son of Joan. Thus Guttorm "i Angestad" should be disassociated from Joan, and have his name corrected to LNAB "Unknown" and a nickname of "i Angestad". Cf. Rygh, p. 145.
Rygh considers Guttorms sons well attested. Two of them, Olav and Faste, appear together in 1494 (citing DN XIV, p. 148); Faste appears with Philippus in 1490 (DN XV, p. 95). Among Olav's offspring, only two are listed without ?-marks by Rygh. Joen Olavsen (profile Blix-182), is marked as the "son or daughter's son" by Rygh, of Olav Guttormson, and so with no intervening, known, person, this link should clearly be severed and the appropriate notes made in the biography.
As a further caveat, Hernelind's research for the later generations relies on secondary sources such as Bygdéns memorial of the priesthood of the diocese of Härnösand, and de Robelin's work on the Skanke family (which I have not seen and which does not, anecdotally, have a good reputation).
Here's the pedigree only from Rygh's article: