Emma- born October 22, 1983
Henry- born August 15, 2001 (Regina's password)
Snow White- born April 15, 1956 (Approximate date of the present day events of 2X15. I believe at some point Emma mentions that Mary Margaret is younger than her. This would make her 6 months younger.)
Prince Charming- born around 1956 (Around the same age as Snow. Both actors were born the same year.)
Regina- born in February 1948 (This would make her 18 when Snow is 10. The events of 5X12 show her birthday to be in February.)
Zelena- born April 15 1945 (Her birthday is mentioned in 5X16. In 5X19 the flashback implies she is around 3 years older than Regina.
Roland- born in early-mid 1979 (He is 4 in 3X03, which takes place around May 2012)
Elsa- born around 1951 (Based on age of actress. This would make her approximately 28 in 1979, the approximate time of the Frozen flashbacks)
Anna- born around 1954 (Based on age of actress and her traditional age in relation to Elsa)
Ingrid- born around 1915 (She is around 35 when she is trapped in the urn on her father's 70th birthday. This would make her around 57 when she arrives in Storybrooke.)
For the following I am going to assume Bae arrives in England in 1859, the year the Big Ben was built. This would make him, his father, and Hook around 200:
Baelfire- born March 23, 1845 (Assuming Neal's birthday from his wanted poster is his real birthday)
Rumpelstiltskin- born around 1804 (This makes him 55 when he becomes the DO, the current age of his actor)
Hook- born around 1829 (This would make him 30 when Milah dies and approximately 35 in the present, the age of his actor)
Liam Jones- born around 1826 (approximately 3 years older than Hook)
Milah- born around 1813 (This makes her 46 when Rumpel kills her, the actresses current age)