I could see Lovelady Powell as Julia, she does have a resemblence to GH. Though, if she was cast, we may have seen the original plan for Barnabas to kill Julia.
The book also states that Julia was to die in a vat of acid, that's the first I have heard of that idea.
If LP backed out after Julia's first episode and then GH take over for her next appearance, it would have made for an interesting comparison
[spoiler]Perhaps after Julia's experiment turns Barnabas into an aged man, he was to get revenge on Julia for doing that to him and then throw her into the acid vat? Would they have been able to keep Barnabas on the show after doing that? Unless Woodard and Burke were still around and then they did the staking.[/spoiler]