I suppose the 22 December birthdate for Jon/Jan was found on the emigration papers you have. (Those are probably called flyttningsbetyg or flyttningsattester or flyttningsbevis or something like that. That is a superb document which most of us aren't lucky enough to have.
It is quite possible that the 22 was misread somewhere along the way in the Swedish records. (The numbers, in particular, are easy to misread.) I see the birth of this person, most likely. You will need to follow him forward in the parish records to see if he married the right woman, had the correct children, and left at the right time. This looks good to me, however. (I have found MANY date errors caused mostly by poor handwriting when I've researched my family in parish records.)
If you join the fee-based Genline site, which has scans of the original church records, you can see this handwritten birth record at the following page number (GID number).
December 29-30 (born the 29th; baptised the 30th) Wastanvik (Västanvik today, probably): a village in the parish where the parents lived
parents: Erik Jansson and Kerstin Jonsdotter witnesses to the baptism: Per Kjellgren, wife Jansdotter, and it looks like the same location where those people lived.
35: the age of the mother
Jon: name of the child
The family as it existed at that time is on the following Genline page. This record still shows 29 as the birthdate but it isn't clear even at the start of this boy's life and it may very well be misread in the next record or two.
GID # 481.63.36900
This shows a parish record called the husförhörslängd in Swedish. (It is abbreviated as HFL.) This word truly has no equivalent but it is often translated as clerical survey record or household examination record. The HFL is set up in a similar way to a census but it is far more detailed and updated continually and not just every ten years. It is the main reason that Swedish genealogy is so easy compared to genealogy in other countries. This particular parish record covers 1835-1839.
Erik Jansson, born 1911 in an unreadable place but since everyone else in the family, including the child Jon, was born there, it must be some sort of indication for Fryksände.
H (wife) Kerstin Jonsdr. (Jansdotter), born 1891 in the same place
Erik, born 10 March 1834 in the same place
Jon, born 29 (which almost looks like 22) 1836, in the same place
Karin, born 25??? December ???? 1839 in the same place
I am not going to follow this man all the way through the parish records. I wouldn't want to rob you of the fun plus I don't really want to make people think that I'm offering to do this for everyone. (I am not.) I wouldn't have time to do any of my own research or even do things I need and want to do for myself. I just want you to see what is available if you only use the parish records and not search in vain for clues in indexes and transcribed records.
Fryksände HFL 1840-1845:
GID # 481.65.105500
Br. (Brukare, a kind of farmer) Erik Jansson, born 1811 Loco (Loco is Latin for here.)
H. (wife) Kjerstin Jonsdr., born 1801 , do (ditto; meaning Loco or here.)
Erik, born 10 March (10/3) 1834 (34), do
Jon, born 29/12 36 (much easier to read in this HFL, but it may not be neat in a later record)(29 December 1836), do
Karin, born 25/12 39, do
Jan, born 24/2? 42, do
Keep working through the HFL and sooner or later you will find whether this is the right person to be your ancestor. It is not hard to do but it can be time-consuming and it is unlikely you will find someone to do this research for free. (I don't want to do it for any price. I have plenty of my own research to do.)