It's a bit of a brain thumper to think of a fruity tomato that is sweet with no tang
... but I finally thought of one - Anna Russian.
Not yellow or a cherry but...
These were so sweet, and tasted like watermelon to me, not a bit like a tomato. I found it shocking at the time.
Now I know better.
Another candidate might be Zolotoy Zapas. This is a determinate or semi-determinate variety with small, firm, orange fruit that were fantastic tasting, with a hint of canteloupe.
I am out of Anna Russian seed but I do have some ZZ if you want them, PM.
Your crosses are exciting, the world needs more great micros so keep up the good work!