Back in 2011, there had been talk of perhaps having a full version of FH specifically for Macs, but KovuLKD (the game's creator) has since left FH, and therefore it is very unlikely that this sort of thing will be put into place anytime in the foreseeable future.
Just as well, FH+ is not official game content, and so its progress is in the hands of Simba/TLK4ever, the one who developed the FH+ mod. To my knowledge, he hasn't announced any release dates or much insight about its progress, and so you'd be better off searching Simba's DeviantArt page for extra info on it. If he is still continuing on the FH+ mod, though, it's likely that it won't be released for a little while.