Is this the same woman? Opinions needed!

Ann Maria MITCHELL is d/o William MITCHELL and his wife, Martha
Baptism (and DOB):
http://ift.tt/1WM5fkZ

Possible (probable? opinions appreciated) marriage to Thomas Dalman:
http://ift.tt/1WM5cFH

Switching to tracing Thomas Dalman, here he is in 1851 - but she's going by Mary and her POB is Biggleswade
http://ift.tt/1WM5fBh

Thomas in 1861 - Now she is Mary Ann and she's from St Luke's
http://ift.tt/1WM5cFL

Might be her in 1871:
http://ift.tt/1WM5fBl

Mary A in 1881 - still from St Lukes:
http://ift.tt/1WM5cFN


SO:
1) is Mary Dalman the same Anna Maria who married Thomas Dalman?

2) is the Anna Maria who married Thomas Dalman the d/o William & Martha Mitchell?

Bonus Round) Why did Mary Dalman indicate she was from Biggleswade in the 1851, then switch to St Lukes for subsequent censuses (and St Lukes would be consistent with the baptism).

Is this the same woman? Opinions needed!