Helena Wayne: the idea here appears to be to transplant some semblance of the Golden Age Batman onto a possible future of the mainstream Batman, and then to time-travel the resulting Huntress from that future to the present. That works reasonably well; but more could be done with it. Since time travel is involved, one could theoretically have Helena wind up in 1977 at some point and spend almost a decade there, if you want to insert her into 20th century history. Just be sure to pull her out of the Crisis before her death.
You might even be able to salvage the Golden Age Robin in a similar way: have him be Dick Grayson Jr., future son of Dick Grayson and Barbara Gordon; and throw him back in time to 1976 at some point, where he ends up teaming up with the original Star Spangled Kid and Power Girl.
I don't think that's in the cards at this point, mind you; but I could see it happening somewhere down the line.