Today both Mykletun (old spelling Micheltun, Mikletun etc.) and Sellevold farms are in Lindås parish, about 30 minutes north of Bergen, the farms are only a few miles apart.
If you have a good map of Norway, the closest township today is Alversund.
Knut Olsen (i.e.son of Ole) was confirmed on May 8th 1823, he was born Nov. 28th 1807 at Sellevold farm, son of Ole Andersen (son of Anders) Sellevold and Kari Johnsdtr. (daughter of John), they were married 28 Jun 1807 in Hamre parish.
http://digitalarkivet.uib.no/cgi-win/webcens.exe?slag=visbas...Ole was from a farm called Vaxstaule (don`t know today`s name for that farm), Kari from Hilland. It was the first marriage for both.
Here is Kari in the 1801-census Joen is the old spelling for Jon/John. The first two people are her parents, John and Martha, siblings Anders, Martha, Synneve:
http://digitalarkivet.uib.no/cgi-win/webcens.exe?slag=visbas...Joen and Martha were married March 27th 1785, he was from Sellevold, she was from Soltvedt:
http://digitalarkivet.uib.no/cgi-win/webcens.exe?slag=visbas...---------
Ole and Kari`s son: Knud Olsen was married to Ingeborg Askildsdtr. (not Sureborg - which must be a misspelling as it isn`t a Norwegian name) 26 Dec 1842 in Hosanger parish.
They also had the daughter Karen Maria Knutsdtr. (daughter of Knut) she was born May 18th 1849 at Mykletun and christened May 20th in Hosanger parish (the records I have access to start in 1849, so I haven`t been able to find Ole).
Then they had:
Daughter Ragnelle b. 25 Feb 1853, chr. 13 Mar 1853
Son Ananias b. 01 Jan 1855, chr. 17 May 1855
Son Knud b. 17 Jan 1857, chr. 15 Mar 1857
All in what was then Hosanger parish.
When Karen had her confirmation in 1864, she was a maid at Nedre Tvedt (lower Tvedt farm) close to Alversund.
http://digitalarkivet.uib.no/cgi-win/webcens.exe?slag=visbas...She is also found there in 1865-census:
http://digitalarkivet.uib.no/cgi-win/webcens.exe?slag=visbas...Same census you find Ananias as a fosterchild at the Bøgevold farm, indicating that his parents are either dead, or poor:
http://digitalarkivet.uib.no/cgi-win/webcens.exe?slag=visbas...And Rangela/Ragnhild as a fosterchild at the Næse farm, says here she is placed there by the welfare service for the poor:
http://digitalarkivet.uib.no/cgi-win/webcens.exe?slag=visbas...Knut/Knud is a fosterchild at the Ly farm:
http://digitalarkivet.uib.no/cgi-win/webcens.exe?slag=visbas...My guess is that their father is dead, because I think this may be Ingeborg/Ingebjørg (different spelling, same name, it was spelled -bjørg when Knut was christened for example, -borg when the others were christened):
http://digitalarkivet.uib.no/cgi-win/webcens.exe?slag=visbas...Says she is a widow on welfare, in her 49th year, meaning she was probably born 1807.
I am not sure I have found Ole, but this is a good candidate:
http://digitalarkivet.uib.no/cgi-win/webcens.exe?slag=visbas...Næse/Nesse is the farmname where his sister Ragnhild is living, maybe he was a fosterchild there too, untill he went to earn some money? The woman in the family he is living with, may be Kari`s sister Brite...
What you need are deathrecords for the Hosanger parish, I don`t have access to them, and also christeningrecords for before 1849... But this should give you a jumpstart?
Good luck!
Heidi