Lofwyr is a significant example of a dragon, even of a great dragon, but he's by no means exceptionally different. If a spirit wants to stick around, by that very decision it has - wants - some sort of association with humanity. Being a spirit doesn't automatically make every single one of them utterly inhuman, or else we wouldn't have animus/anima, players, and all the other 'I like to interact with humans' types. We wouldn't have a spirit spearheading one of the top megacorporations in the world. Making them otherwise may emphasize their difference from humanity, but it also would completely alienate them from humanity, and essentially eliminate the idea of a free spirit contact in the first place - so while they aren't all Buttercup, they aren't all Xkq'd'wrks from Z'na'd'po'k; your implication is that they are, and is thus at least - more - unlikely, since Shadowrun has portrayed many if not most spirits as being innately interactive with humanity, even to the point of them existing because of humanity - e.g. spirits of man.
As for the 'what do they see with' and the like, please - you're seriously asking about the biology of something which does not have an innate physical form in the first place? C'mon. They see with whatever they want to see with - but the default assumption is that any creature in Shadowrun generally sees in the standard ROYGBIV wavelengths. Anything else requires a power, such as being dual natured, thermographic vision, and what have you.