@enoshimajunko It's absolutely a lot. Having twins, being faced with the decision to take in family's kids, and then ALSO having 3 young kids yourself... Any one of those three factors is overwhelming, let alone all three!
If they are placed in a traditional home, just reach out to the caseworker to discuss that you would like to be involved in the kids lives.
For me personally, I was a foster parent because my mom (who I am currently estranged from) was, and had a teenage girl. My mom didn't want to deal with the girl and sent her to her biological mother's house for weekends because my mom "didn't want to deal with her". She was caught, there was an investigation, and since I already had a close relationship with the girl, they asked me first since there were no safe family members. I was told I basically had 30 minutes to decide to either take her in or she would be moved to another school district.
I took her in, and I thought "okay, I work with foster families for my job, I know her, I got this" and it was way harder than expected. There was a stretch of time where she had a doctor's appointment or caseworker appointment or CASA appointment every single weekday for two straight weeks.
Even if the kids are fine and manageable, dealing with the rigamarole of foster care is time consuming and emotionally exhausting. It puts a huge strain on families, and the scrutiny for non-licensed foster parents (usually family) is higher and more intensive. You have to use the state Medicare, so any doctors appointments require 400 calls to see who takes it. The kids are often enrolled in therapy or other services (like what I do) which often require driving and appointments. The kids have scheduled visitation, which will require availability and restructuring your day. Last minute changes often happen. It's a lot of extra work, and I don't know you, maybe you're a lot stronger than I am, but I would BREAK dealing with that + the extra struggles of the kids that now have trauma + your own little ones + twin newborns/babies.
If you're a caring and loving person, it can absolutely feel like a failure or an act of cruelty to say "no" to a situation like this. There are many times I have to have very real conversations with well-meaning and amazing and loving foster parents who are very clearly drowning but are determined to keep up the situation anyway because they are afraid of the unknown and what they might be putting the kids into. Many times, when overwhelmed foster parents I see make the decision to let go, everyone is happier for it. The kids often wind up in homes that are better suited to give them one on one attention and the foster parents no longer have to carry on with an impossible juggling act.
Sometimes being realistic about the circumstances and saying "no" is the more compassionate and loving option.
I hope my tone here is not coming off as patronizing or cold towards your situation. At the end of the day, you are going to know what you can handle and what you are capable of far more than I would. I just see this scenario often and not everyone has the experience with the foster care system to know what they're getting into beforehand.
If this is ever something you want to talk about more on, please feel free to message me and we can discuss more at length. Especially if you do decide to foster and want to talk about it, there's no expiration date on that offer. No matter what, it's a hard decision with a complicated answer.
Sometimes kind people need "permission", so to speak, to say 'no", and my intention with writing all this to you was just to give you that permission, not talk you out of it one way or another.