Gee she’d be round knocking the door if I blocked her
Of course she would, Chrissie.
This is, after all, the woman who has barely split up with her ex, but already has her sights on a new beau, tellingly described as a "rich man", who she is looking to install in her home, or to install herself in his, so that she has another victim to financially abuse.
Never mind what that does to her children's emotional security, never mind waiting a year or two to make sure the new man is safe & kind around children.
Not only this, but she has hatched a fuckwitted plan to get the Rich Man's kids to move in with them so that she can leech even more money - tell me, has she even mentioned the mother whose life & happiness she is planning to ruin by taking her children away?
Or thought about her own children, & how they will be affected by it?
OP - she is perfectly willing to ruin another woman's life by taking her children from her in order to get her hands on some bloke's cash.
The fact that this is a harebrained scheme with no chance in hell of succeeding is immaterial.
What is material is that she would have no compunction in doing it.
What do you think she is going to do to you when she realises that you are no longer her obedient cash cow?
I think you need a solid plan in place for how you deal with the repercussions, because there will be a backlash & your "friend" is likely to want to punish you.
She is not your friend. She is a financial & emotional abuser, & you know what happens when people finally wake up & start standing up to their abuser.
You 'sound' much firmer in your responses & resolve now.
Please discuss this with your DH & make sure you are both on the same page.
Because once you say no, & she starts knocking on your door demanding reasons (which you do not owe her, not wishing to comply is reason enough), you will see that to her, you only exist to service her wishes, & as soon as you step back from that role, you are going to see a very different "friend".