How it would work, if it worked, would be this:
dustaven and marxdarx would negotiate a babysitting fee at a reasonable rate lower than the normal rate of the daycare that the Mad Scientist (Dustraven's son) goes to.
The Mad Scientist comes over to play with the Little Fayoumis, with Marx supervising. (I think the two of them will require a lot less supervision than Tommy and Angelica did with the LF.) The kids are a year apart, and the extra year that the Mad Scientist has may help make up for the Little Fayoumis's bossiness. The Mad Scientist is well-behaved, from what I've seen, but may require some prompting on some things (I saw that he needed to be told three times that it was bedtime).
dustaven and trystan_laryssa go to work. With me. Yay another shift together!
The grownups see how it went, and decide whether or not to repeat it.
If all goes well, the junior fen will hit it off well.