Toole's book is available online as a googledoc, but I think it essential (and of course more ethical) for anyone interested to pay for it, however it takes to get a copy. It is a must-read if anything is in audio for the serious layperson. I called it 'masterful' in LinearAudio magazine a year ago even while taking exception with some historical contexts and uninterests. It is, frankly, like reading Steinberg or Rosen on classical music, Broadbent and others on wine, and Hughes et alia on art, to name only those where I have some experience: a headshakingly impressive experience from a master.
There is a third area of 'room awkwardness' related to reflections, the lower midrange. It is as important as any, if not more. Admittedly perhaps subtler, given ear sensitivities. FT knows all of this and does get into it in his book, although in my and others' view he scants it to some extent. The (Roy) Allison effect, as it is sometimes known even though it was presaged before Allison's 1970s real-world room measurement papers by earlier researchers and also elaborated afterward (notably by B&W's Glyn Adams), shows that when the distances to the three near boundaries --- front wall, sidewall, floor --- are similar, the result in almost all domestic situations will be a notch in the lower midrange (90-350Hz or so). Btw the floor is not privileged, gravity having no effect. And it does NOT have to do with first reflections only, but tangential and oblique as well; see the well-known Olson cubical drawing of sound source near corner. Allison misleadingly termed this an LF effect, although it's typically higher than most of us can sing, hence my term lower midrange, as in looking at a musical score.
The solution is to design systems such that the driver(s) covering this range are not only multiple (a recent happy solution) but also forced to be staggered wrt to the three near boundaries, preferably with one distance close to a boundary, like the floor or front wall. FT says the AE suckout is broad and not so frequency-specific, although that's not what Allison and many others, including myself, have found from our measuring and listening. It is altogether audible, and sometimes initially euphoniously thinning, yes, but not natural or accurate over time to an experienced ear. (See amusing Gordon Holt Stereophile review mid-1980s of the Allison Nine, to the effect that 'I eventually came to realize that all other speaker systems have been doing the lower midrange wrong', etc.)
As for distortions and linearity/nonlinearity, I suggest thinking to first order of linearity as having to do with the y axis rather than the x axis. More important, there are hoary demonstrations showing how profoundly unimportant these distortions are. Dr. Mark Davis (1978 High Fidelity magazine article) and also others have described a well-known Amar Bose experiment at MIT using an audio chain comprising driver, mike, amplifier, second gain stage, and headphones. He drove the driver with various signals, soft to very loud, but kept the levels at the listener the same. Guess what? Distortions become audible only at near-destruction overdriving. (Email me, consulting LinkedIn or F/B, for a copy of this fascinating article on speaker radpat and what we do and do not hear; Davis works at Dolby.)
A second (anecdotal) datapoint was the comment from the great musical acoustician Arthur Benade to Allison and Edgar Villchur, after publication of their AESJ paper showing no audibility of Doppler distortion from hifi loudspeaker systems deployed at typical levels. Benade pointed out to them that this finding also surely meant that the other bruited worrisome distortions (TH, IM) must also be inaudible short of gross overdriving.