Wow .. yeah thats a lot of thinking you have been doing today..

Of course anything is possible .. The only thing I would say you might want to look closer into is the following...

~ Since for the time being you are/have been estranged from all 3 of your children... Could you be thinking about having another child that NOONE can keep you from raising as you want. YES, but I would want father participating, just not running the show
~You mentioned finding a Man and having some sort of contract drawn up to assure financial support??? That's all fine and good but there is no way to guarantee support from anyone... I know people rich and poor and trust me they are not always receiving child support for a variety of reasons. I know, it is like with stock - past performance does not guarantee future result. But still, I would want Robert to review past tax returns.
~ You said it would be 20 years of hard work but you would end up with a meaningful relationship ???? Just because you raise a child from infant to your adult doesn't guarantee a great relationship.. Same as your current relationships with your kids won't neccessarly mean the relationships won't improve. The likelihood is far greater if there is uninterrupted residence at home with me, for one, and if there are no people maligning me, for another. Nothing is guaranteed, but the chances are greatly improved. And even if I do not end up with the best r/s, I still will have accomplished raising a child from cradle to college.

Again anything is possible I'm not being a downer here ..

Just some thoughts...