My alien creatures are arthropods: multiple limbs, segmented bodies, etc. Is it possible for them to walk if their legs are placed in a x formation in thier pelvies or similar to the shape of this symbol >< in.also they may or may not have a thorax.and would they need to be in a position similar to praying mantis, spiders and crabs? If this helps, the planet has low gravity, so not as much weight would be placed on them when they walk. All I need to know is if would it be a possible form of locomotion? and could it work bipedal as well? edit-legs are positiened at a 45 degree angle from the pelvis that explains the x or >< shape i was talking about would this make problems for locomoting
The limbs, as per the first centauroid sketch, are in perfectly normal mammalian posture. There's not enough of an offset to make the legs look at all buggy. The only significant difference obviously visible is that the hands are much longer than a humanoid centaur, and that's not a problem at all! Since these are arthropod centaurs, I don't see anything immediately concerning in this sketch.
The second centauroid sketch is a little difficult to interpret, mostly because it's a 2D stick figure image without any perspective. Assuming that this represents a face-on perspective, and that the 90deg perspective would essentially depict "straight" stick-legs, this looks like classic genu valgum, where the hips, knees & ankles form an "X". I assume that this is what you meant by "X shaped" or ">< shaped". Since the creatures are fairly light & the gravity fairly low, I don't see any reason why they couldn't locomote with ease.
I'm generally of the school that looks at creature design as the end product of some kind of evolutionary history. Therefore, your X-legged walker must have evolved to this point; thus, it must work.
The only potential difficulties I could foresee are a wide body that would interfere with the "X" shape. If the posterior segment were somewhat triangular (broad dorsum which narrows towards the ventrum), then the legs should be able to move freely without scraping against the body.
Alternatively, keeping the thighs perpendicular to the ground while leaving the hip-knee-ankle angle in its "X" configuration, I should think these creatures would have some pretty incredible stability while scooting around the landscape!
I'm not at all sure what to make of the other sketches: they look like frogs or buggy reindeer heads or something?