Is it considered just for the first wife to endure hardship or difficulty because the second wife refuses her husband to visit her during her turn, and does childcare fall under the division and turns, and is she sinful for communicating with her husband via text messages while he is at his co-wife's house, and is it just for the husband to break his promises of spending Eid with her and their children?

A woman's interaction with her co-wife should be based on kindness, and patience is the best solace in difficult situations.

The wife whose turn it is has the right for her husband to spend the night with her, and the day follows suit. The husband is prohibited from entering the other wife's quarters except out of necessity. You are not permitted to communicate with your husband while he is with your co-wife, except out of necessity. There is no harm in him coming to pick up his children, but his entering your dwelling is subject to the aforementioned ruling.

If your husband promised to spend Eid with you and your children, he should fulfill his promise, as fulfilling promises is commendable. If the day of Eid coincides with your turn, then his spending the night with you is your right.