What I said about pianos Will said about guitars and Dick about concertinas - musical instruments assumed being "the same" may sound differently and we do not know the causes.
This is one reason that for my own part I would never get the idea ordering a new instrument hoping for a particular sound or a tone I did not find anywhere else, I'd rather pick an existing instrument. I might however order a new instrument for a particular purpose if there were not one to find to any or comparable cost.
Will, there is NO acoustical resonance from ANY wooden parts in squeezeboxes, forget that! so there is no reason comparing with your guitars! Your question No2 is an "impossible one" but a simple answer is YES but not necessarily dependng on what "qualities" you select.

Dick,some comments to quotes:

- "they all have steel reeds [i assume made by the same man]"

RE: That's a daring question, if they are oldish Wheatstones likely had more than one man processing reeds and quite a few tuning them.If very late it might have been "the same man"...

- " they all use syacamore to resonate the sound".

RE:Like I said to Will - there is NO acoustical resonance whatsoever by the wooden parts in squeezeboxes.There is an old misunderstanding that since the parts may vibrate they also cause resonant sound

- "1 .do aeolas have longer reeds?"

RE: Mostly Aeolas have somewhat longer reed scale but I have come across extended range ones seemingly using contemporary standard scale also used for sixsided

- "2.is there a difference between swedish steel and japanese steel[as regards acoustics, or is it some special treatment of the reed that improves the sound?".

RE: We will not know unless making a proper metallurgic analysis but even so there will be doubts regarding the hardening process which may differ more or less.Summing up, as I mentioned regarding the delivered steel from Swedish steel works, the raw steel specifications seem to have been basically identical it is the treatment/processing of the *reed* itself frame AND tongue done by each producer that is responsible for tonal differences

- "one concertina maker said to me steel is steel it is the wood that is more important, now this seems believable we know that wood on other musical instruments makes a big difference, but what do we know about steel?"

RE:The steel effects seem to have been pretty well studied, the "treatment menthods" as well, effects from high precision processing accuracy too - all important for sound qualities.
The effects from various reed block material, "sound board"(accordions=reed pan(concertinas) and general box materials have been studied by Richter and effects seem to be very small if any.
Geoffrey Crabb has told me that Crabbs experimented in the 1970s with sycamore,beech, beech ply, balsa,aluminium and moulded materials like resin for pans, and they found no significant differences.Richter had made similar tests with similar negative results.

The conclusion for the time being seems to be that the reed remains being the most important sound quality factor (but it IS important to separate specific reed qualities!)and (specific) wood seems to be misunderstood as being important( often from unjustified comparisons with string instruments). There are lots of wooden parts in a squeezobox however and these, along with the measures of related compartments, may have acoustic effects modifying the original reed tone. One such effect is the volume underneath the cover/end plate.
The larger it is the more mellow the tone it seems. The more or less covered area is important one way or other.It may have a general damping effect (taking firstly high overtones out) possibly it may (theoreticaly) have some "formant resonance" effect i e similar to the trachea and throat for the human voice. That means it might add a "flavour" to the emitted sound (by the harmonic resonant frequences related to the measures of the compartment between action board and end plate).When I picked up some tone spectrums 20 years ago I could not detect ANY resonance effects in the concertinas at all however!!
The differences in tone spectrums seemed to be related merely to absorption/filtering and consequent reduction of components in the higher spectrum but the experiments should have been continued and improved to know more.
The "fretwork" also has got influence mainly related to the degree of openness but I have a guess that the amount/length of edges in the fretwork might have some effect, meaning that the more elaborate it is but with the same total opening area more filtering/absorption of high frequences might take place. This should be easy to check lab-wise.
So called "baffles" ( which do not act as common acoustical loudspeaker *baffles*) - wooden or cardboard covers underneath the end plate do have a dampening effect.
I have experimented with asphalt materials covering surfaces underneath the endplate to absorb high frequences. I have a very subjective opinion the effect might be greater than with cardboard.
Lab test are always necessary to evaluate all such trials.I do use various "baffles" in most of my instruments