Good work jsegaloff!
The birth record for Otto has to be him. His children are known to you, from the opening query you posted, and therefore he is unmistakable in the 1910 census. The birth-baptism record you found is for baby Otto with the same birth date as the 1910 states.
I suspect the birth you posted fir his father Johan Hansen is probably correct as well. The birth date is one day different than stated in the 1910 census posted for Johan. It is a good idea to go to a person's marriage record first, working back in time step by step. The marriage record for Johan Hansen and Kjerstine Halvorsdatter in 1846 in Fet states his father as Ole Hansen, unless Ole is a "best man"/witness only. The birth record names Johan's father as Hans Hansen.
Kjerstine Halvorsdatter, Vindland (or Windland) is the name for Johan's wife in the marriage record.
Busy day ahead here, must run. Again, great job!