Regarding LFS, I don't think you read their documentation: http://www.linuxfromscratch.org/lfs/view/development/ Otherwise you wouldn't think of something like this as simple, because it isn't.
Then, again, go through our compiling guide. It is the MINIMUM you need to run the basic Whonix configuration on whatever base you fancy. Though again, depending on both your system and your abilities, it will take you days, if not weeks to finish this because there are massive amounts of data which need to be compiled which simply isn't doable in 10 minutes.
If you are really serious about compiling Whonix for a custom base, which like mentioned takes time and care, I'd start here: http://www.aboutdebian.com/compile.htm It is a good guide, explaining the basics and showing why this can't be done simply.
What? Do you know what Debian Minimal is? It is a NETWORK install. That means, it is a small FILE which while installing gets the REST/ENTIRETY of Debian from their servers. Debian Mini base Whonix thus is the SAME as the Whonix you can download from our website.
And Debian from Scratch? Why? What advantage do you gain? It is safer or anything, it is just so you may learn to compile. Their'd be no advantage. Or to quote Linux.com:
Debian From Scratch (DFS) is not everyone's distribution. It's not an easy install. You need to know your hardware. You need to be prepared to take pains. And, at the end of the process, the result looks like any Debian system installed by another, usually easier and quicker, means. So why take the time?
One answer is that DFS offers a chance to learn about aspects of installation that you've never explored. Even if you have no background in computing, the do-it-yourself mentality of the free and open source communities is contagious. You may want to explore DFS out of sheer curiosity.
So what you are doing by basing Whonix on Debian Minimal or DFS is getting the SAME as the Whonix you can download from https://www.whonix.org/download/
If you want to learn how to compile and do things from scratch, this is of course great, though I feel like you should start with easier stuff, like the guide I linked above.
Have a nice day,