Hey there. My guess is your exporting incorrectly.
I work with blender as well, and despite working in mm, or working in the mindset of 1 UNIT - 1CM.
Somehow things still get screwed up, maybe it's a scale you applied in object mode, and didn't apply?
Either way, I recomend importing into either Mesh Lab or NetFabb.
There was one case where I exported at 11cm, working in the metric scale, and the model size came out at .11mm. This was because while I was working in metric, I had set the global scale to be .01
So that 1M would be 1CM
(I had this set up, as my default scene)
What texture problems are you having exactly? You know that material colours won't display right? Only UV Textures.
The keepsake box may actually be that expensive depending on what size you uploaded at, and if it's hollow.
Don't forget to check what scale you upload at.
Can't help you with the "sciFI pyramid" All I see is a square.
The orb house may be from again, scaling in object mode.
I don't know what it is, but when you go from a high scale, to .001. Some areas get twisted if you do it in object mode.
Sometimes applying the scale fixes it, sometimes no.