The OP's experience is with a parametric modeler where dimensions are either driving or driven and geometry is either "normal" or construction (think of drawing board).
One of the 2 side Flat Patterns.
(I'm not sure if r2006 would allow multi-body sheet metal.)
If not, it is a simple process of doing one at a time.http://files.engineering.com/getfile.aspx?folder=e196d18d-77da-4f63-b929-147b54891f8b&file=Side.PNG
I always expect to see effort on the basics.
In fact it takes no more time or difficulty to sketch correctly.
http://files.engineering.com/getfile.aspx?folder=b72c1f23-a7dc-487c-839e-611d4264da3f&file=Fix_Sketch.PNG
This one is pretty easy.
First thing I did is "fix" the sketch as it appeared no real effort on getting it constrained. (I didn't change the dimensions.)
Then I offset the faces by zero.
Thickened them and converted to sheet...
First thing I notice is that there are no dimensions in Sketch1.
What happened to the dimensions?
Second thing I noticed is that Sketch1 is not placed with obvious symmetry about the origin.
Third thing I noticed is a fillet in Sketch1 that appears at one "bend" but not on the "symmetrical"...
Not the prettiest threads, but if you fix this problem it looks like it will work.
The thread in the Cap is disjointed from the cap along most of its side.
(see attached)
http://files.engineering.com/getfile.aspx?folder=ab34e311-e7fc-4352-87ff-cba2947e3e3c&file=Threads.PNG
Inventor has already told you it is unresolved. How could you see it if Inventor can't "see it"?
I am not even sure what you mean.
Is there a grayed out node for the part in the assembly component browser?
Delete the node.
We routinely 3D print threaded holes (down to around M4 or 5 as smallest) (usually larger). You will have to model the threads and allow a bit of extra clearance as the 3D printing process is not particularly precise.
I use a lot of construction lines - none of them infinite.
If you go into the line command and right click you will see construction
or
create normal line and then there is an icon in upper right corner of screen to toggle it to construction.
Project Geometry of the origin axis is, in effect...