TStop4Me, you are right that the boot influences the way in which your body and foot interact with the blade. E.g., the forward/backward tilt of the foot, and the amount of forward/backward bend, both have a huge effect on the way in which the foot interacts with the blade. E.g., to a large extent, it is the downwards projection of the foot that interacts with the blade, and if the foot is tilted (as it is in almost all figure skates), that length is substantially less than the untilted length of the foot.
However:
(1) Both that tilt and that bend can be to some extent modified by the insole. I would argue that most people can be made more comfortable by such modifications, that they or their fitter makes, rather than relying on the standard shape the boot maker assumes - though I would also argue that such parameters are a significant part of the reason why many people feel more comfortable in some brands of boot than others.
(2) Think of this in terms of simple physics: Because the soles of figure skating boots are extremely stiff, the outsole length can have virtually no effect on the interaction between the body and the blade. That is to say, the forces delivered between the body to the blade are not significantly affected by outsole placement or length. The placement of the blade on the ice is also unaffected by those things, UNLESS you mount the blade relative to the outsole, rather than relative to the foot.
There is of course one major exception to (2) above: the length of the boot affects how close the feet can come together without hitting each other. One of the tenants of skating's "neat feet" is that the feet should often pass or brush as close to each other as possible. But the audience and judges don't see the feet. They see the boots. And it is the outside of the boots that constrain when they do and do not touch. The outsole is part of that.
Regardless of boot maker's recommendations, it makes sense to me for each skater to look at their equipment functionally - that is, if they skate better with a longer or shorter than recommended blade, or with a blade whose sweet spot and toe pick is in one or another position, etc., they should pick the one that works best for them. In other words, the boot maker's recommendations should only be seen as a first guess at what works best, for that skater. (I suppose it might even be possible that some skaters would be better off with slightly unequal blade lengths, though I've never seen anyone do that.) In any event, now that the original poster has a pair of skates and blades to work with, he or she can experiment with modifications that achieve what they want. Unfortunately, if he or she decides on a different pair of blades, that will cost extra - which is why it would be nice if the original guess was right, but that is sometimes too much to hope for.
However, the outsole placement and lengths does affect the stresses that occur internal to the boot itself. I damaged a pair of skates, by using a mis-positioned mounting point. In particular, an inexpert fitter offset my blades sideways to make me balance better, instead of modifying the insole to achieve the same thing. Some boot brands and types are made to allow for that. However, Klingbeil, which made those boots, specifically specified that they should be center mounted - and were not designed for the physically stress created by an offset mount. And the boots gradually twisted and warped. In principle, Klingbeil could have voided the warranty for that, and the warp did affect the boots in a number of ways.
Likewise, it is conceivable that a given boot brand or type might not be designed to take the physical stresses associated with mounting the blades more forward or backward, or with a different length than intended. I simply don't know whether that is true.
BTW, Edea is very atypical in fit theory. Most reputable boot brands try to create approximately equal pressure all over the foot, with the possible exception of the regions behind and ahead of the part over the ankle, and maintain that sideways ankle reinforcement is absolutely critical to the foot health of skaters. They use heat molds and in some case custom fits to create those effects. Edea more or less claimed that you only need pressure contact at the back of the heel, and a portion of the tongue, and that proper fit and boot interaction is obtained by squeezing those two points together on the foot. I would claim that this is a clumsy - and for many people, uncomfortable - way of avoiding making it possible to do real heat molds and real custom fits. This philosophy was explained in a video which I can't find on Edea's site any more - so perhaps they eventually realized this wouldn't work well for a lot of people. But they still lack the easy heat molding technique, and true custom fitting, that other brands have long employed. In fact, as far as I can tell, you can't even specify to Edea different relative widths for heel, midfoot and toe, as you can for most of the other major figure skate boot brands - so some people might end up with issues like squeezed toes, or loose heels, etc. The loose heels can be fixed by inserts or other adjustment, if you know what you are doing, but the squeezed toes may not be, in some cases, especially if the squeeze is too close to the bottom of the foot, if the problem is too severe - in fact, an expert Edea fitter told me that MY feet, which have wide toes, could not possibly be accommodated by Edea boots, for that and other reasons, no matter how the boots were modified.
That said, Edea likes to show pictures of "traditional boots" vs "Edea boots", in which the inside and outside shape is radically different. However, if you look at other modern figure skating boots, most of them don't actually look the way they say that "traditional boots" look, and are somewhat closer to the way they say Edea boots are shaped. I think you need to take any boot maker's marketing hype with a healthy dose of skepticism.
The best fitters have learned, partly through a long process of trial and error, what modifications to make to boot maker's recommendations, for each skater. It seems to me that some of the biggest problems arise when less knowledgeable fitters take what the boot makers say as absolutely correct.