Hey Sunshine1111, here for you along with EZE.
You've done a lot of work to get to this point, including being able to say that what has been happening is abusive.
Sounds like you've made your decision, and now there's a lot to figure out in the leaving process, with your safety and the safety of all the kids being paramount.
It's OK to worry about everyone's safety. You can prioritize it as: you first (because if you're not safe, you can't help anyone else), then the kids, then him. After you and all the kids are safe, if you still have concerns for him, we can talk through options here (well check calls etc). Just make sure to keep you as the #1 priority. It may feel weird yet it's true.
Can I ask, how old are your kids? Ages can be a factor in figuring out better (or less worse) leaving plans (i.e. do you need to "do it all" for a baby, vs teens can process some of what's going on and pack their own stuff).
Another logistics thing to think about is taking a little time now, before the weekend, to put your important documents (passports, IDs, birth certs, etc) somewhere safe (like a rent-a-PO-box where only you have the key, for example). If you have car keys, make sure they are close to you as much as possible, maybe make an extra set and stash them in the PO box or with a friend or neighbor. Consider picking up an extra phone charger at a thrift store. If the kids have important stuff at your BF's place, and they aren't with you right now, think about low-key moving the stuff elsewhere.
I understand the challenges of having the kids go to the other parents' house when it looks like there are no other options. Are there any safety issues at Dad's, or were the issues more adult relationship vs parenting problems? If Dad is "okay enough" and they will be safe there, and if he will cooperate with a "temporary" parenting time plan, that may be your best bet. Other options include (if the kids are old enough) reaching out to their friends' families to see if the kids can stay with them for a week or two. You mentioned being alienated from a lot of relationships. As EZE mentioned, I suspect a lot of those people would welcome you back. It's hard to reach out for support, but doing it for your kids' sake may help.
In terms of the homeless shelter, just ugh

like you have to make yourself worse off to get help. So sorry how that turned out. Not sure if you've looked into it, many churches/faith communities would be willing to ask around and may have members that would put you up. You wouldn't have to share the beliefs, it would just depend on your comfort level. Some churches are more specifically religious and some are more like service groups, but my guess is that either end of the spectrum would at least ask around or could connect you with alternative short-stay housing resources.
You may have already heard somewhere that leaving can be the most dangerous time in a high conflict/abusive relationship. Not sure if you've leaned on them yet -- the DV hotline is free and anonymous, and is not only for phone calls, but also texts and chat:
https://www.thehotline.org/they will have a lot of good feedback on how to stay safe now that you've decided to leave the relationship.
I know you're juggling a lot right now, so I'll wrap up here. Let us know how today has been going, whenever works for you.