In regards to hagar, there is only one reference I was correctly point to that refers as wife. Gen 16:3, the remainder of the references are as follows:
16:6 - Abraham refers to her as "Your (Sarai's) servant...."
16:8 - the angel speaks to hagar and addresses her as the 'servant of Sarai', not the wife of Abram
, represents God's view of things
21:10 - hagar called "slave woman" by sarai
21:12 - God speaking to Abram refers to hagar as "maidservant", not wife and
25:12 hagar is refered to as Sarai's maidservant and 'the Egyptian.
Jacob's case he was tricked into marrying the first one, the 3d and 4th were proxies for the first 2 wives - surrogate wives.
In both cases, they existed BEFORE the Mosaic law was in place regarding the strict exemptions placed on plural marriages. It was tolerated, but not approved.
You forgot one. Hagar is also referred to as something else, besides wife, handmaiden, etc.
Gen. 25: 6
6 But unto the sons of the concubines, which Abraham had, Abraham gave gifts, and sent them away from Isaac his son, while he yet lived, eastward, unto the east country.
Oh, and I forgot to mention...
The Mosaic law was given by the God of Abraham, Issac and Jacob. To bad God is the same yesterday, today and forever huh?