Actually, it doesn't make it easier to understand considering the most prevalent form of romanization is the Hepburn system, moreover the wapuro system recognizes ファ as "fa" not "fua", as well as the Hepburn system. Using the wapuro system of IME, if you type "fua" you get "フア" not "ファ". So to say that transliterating ファ as "fua" is helpful is pretty false, since using Wapuro, you'd either have to type "fa", "fula" or "fuxa". The latter two have little resemblance to the phonetic intention of ファ, which is the sound "fa". The purpose of ファ is present the non-Japanese sound of "fa" because katakana is used for foreign words (and by extension sounds). Even the case of you saying that "フ" is romanized as "hu" is inconsistent since you were previously relying on a different romanization system where earlier you used フ as "fu". My point being, no matter how you split it, "fua" will always be フア to an English speaker using IME input which is based on the Wapuro romanization which itself borrows from the Hepburn as well as other systems. So to say using "fua" makes it easier to understand "ファ" seems like a very weak argument considering the prevalent forms of romanization used in the English language.

I said according to Wikipedia that his Japanese name comes from "Baldanders" which is not a far stretch from バルトアンデルス despite there being not diacritical marks on the ト, which is really the only flaw in the argument. Especially if you consider the fact that as BoB said that n the strategy guide it said the name came from a Nordic deity. The Nordic language is a Northern Germanic language. So the possibility is quite strong, but I'd have to see it from an official guide to be sure. Also, Barthy's (my nick for him) ability to shape shift between human-like form and his fal'Cie form does lend it to the mythos surrounding the Baldanders. I have yet to see a proper citation, but the association between the two seems common enough given a quick Google search. Apparently, in the Spanish as well as the Italian versions, his name is Baldanders as well. So the evidence seems to be stack against you.