This has felt like a bad dream and I haven't even been able to type it, let alone process it.

SO found out on Friday he is being laid off effective June 3rd. Between 2 BMs, he pays almost $5,500....Yes, that is not a typo. He agreed to ridiculous sums during mediation to help his guilt.
Backstory:
BM1 who has SD15 and SD12 is a reasonable and responsible person. She truly does need the $ of her child support. She is frugal, plans spending in advance, and works with SO and I to keep additional costs to a minimum. We feel badly about having to lower child support and will work with her to try and come to some agreement.

BM2 who has SS5 and SS4 remarried 3 months after the divorce (her argument she was a "struggling single mom" who "only" made $90k per year without child support). Technically, one of the kids (SS5) is not biologically SO's.....she cheated with her ex. SO signed the birth certificate and tried to make things work. Then 1 year later she when things were on the rocks she "accidentally" got pregnant with a "miracle" baby after telling SO she couldn't have more children. She also now has a new baby with her husband #3 and got pregnant 1 month after getting engaged to him.

My question pertains to BM2, who lives in Texas (we are in NC). Has anyone filed for child support modification in Texas? We just got a letter saying we are eligible for review, and it could not be better timing. Is this one where you just file your financial info and it just gets ruled by a judge? They letter states we can request a review and state our reasons for seeking one.

Our reasons include:
-SO is unemployed and has zero income (he will get a severance that will last a few months)
-One of the children is not biologically his
-SO signed the mediation agreement because the boys were in an expensive preschool and BM2 said she was a struggling single mom. One of the boys is entering public elementary school and BM2 was engaged 1 month after the divorce, pregnant 1 month after that, and married 2 months after that.

How much does the state expect you to lose to pay child support? Does your household expenses go into it? Do they expect us to lose our house in order to pay child support? Do they expect you to sell the house and use the money for child support? Then we will have nowhere for SD15 and SD13 to visit us EOW and during holiday breaks and summer time, and nowhere for SS5 and SS4 to visit on holiday breaks and summer time.

I'm trying to figure out how likely we are to get a reduction, since his child support amount was decided in mediation and not by the state. I believe the state max on child support is somewhere around $1,800 for 2 kids. I was saying we should propose to lower it $X (to be decided by the judge) while he is unemployed with an agreement to raise it to the state max of $1,800 once he is employed again? I do not want to go back to paying that wench $2,900 for two kids, one of which isn't even biologically his.

Any advice? Anyone go through something like this in Texas? Please any help would be greatly appreciated.