In theory, yes. A filter is known as linear if it is both additive and homogeneous. For an additive filter, the filtered sum of signals is the same as the sum of filtered signals. (Homogeneity means that gain or attenuation can come before or after the filter.) Most digital reverbs, including all convolution reverbs, are linear filters.
In practice, also ...
An IR is made from a space, not a source, so at best, you could use that blasted miracle speaker as the source hardware, playing into some space that could be tuned properly for it and produce an IR from that, but you wouldn't technically be capturing the sound of the speaker, but the response of the space into which it's being played.
It is very cool, ...
Have you tried worldizing your samples? It won't cost you anything but your time and you'll undoubtably learn a lot in the process.
Also, try reaching for complex delays in lieu of reverbs. Soundtoys EchoBoy is a great choice if you have it, otherwise nearly any delay plug will help get you started.
The reason that Waves store the files in a 'wir' format is to make them proprietary, thus preventing you from using them elsewhere. You would have to reverse-engineer the 'wir' file format, extract the impulse, then move the impulse to another system before you could use it. Probably not worth the hassle.
Print the stem only reverbs to an audio track, then print the full mix with reverb to an audio track, line the tracks up to start at the same time, solo them, and invert the phase on one of the tracks if you hear anything they are different.
In my experience with using various non-IRs as IRs in convolution reverbs, the effect has to be prepared well because it is odd / nonrealistic even in small doses, but definitely changes the emotional impact. For a while I was very interested in convolving human speech with bird calls, which does some very fascinating things.