Well, the Hilton Lake Buena Vista is owned by Tishman, which also owns the Walt Disney World Swan and Dolphin hotels. (I know you know that, but other readers might not.)
http://www.tishman.com/portfolio/
Whether the Hilton LBV gets renovated will depend on if Tishman wants to continue spending their cash on renovations. They just poured money into the Swan and are currently renovating the Dolphin. I could see them wanting to go a few years without renovations on the books. (I have no clue if they are renovating other properties they own.)
I want to say they will re-flag instead of renovate. But, if Wikipedia is correct, this hotel is being managed by Hilton. If that management contract is multi-year, that would make re-flagging to a non-Hilton brand difficult, if not impossible.
If that Hilton management contract ends soon (or is cancelable), there aren't a lot of options in terms of chains. They wouldn't want to undercut themselves by choosing a Starwood brand. And, with the Marriott/Starwood merger, they probably wouldn't opt for a Marriott, either. (There also may be geographic restrictions in place that prohibit a second Marriott or Renaissance branded hotel so close to the existing ones.) I suppose it could become an InterContinental or Crowne Plaza. Tishman already works with InterContinental. A long shot would be my old employer Radisson.
I almost tempted to email Tishman and ask. I wonder if that would yield any information.