The Process AFTER creating your .dae

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Okay here are some things you should keep in mind (Prepare yourself, wall of text incoming! ):

Oh and also, on my actual creation, the log tells me I have a lot of stuff that's incompatible with ModelView. How do I, in Maya, like look up exactly what creations I've put in? Really appreciating help!

First of all, to clean up your scene, click on Edit>delete All by type> history. (Non-deformer history if you have a skinned mesh)

Then click on window> Outliner. That opens a list of all objects in the scene. The only thing that is allowed in your scene (other than the standard stuff like the viewport cameras) are your mesh and joints if its a rigged mesh. Delete everything else! (NURBS curves, groups, Locators...) If your mesh is in a group, click on it and hit SHIFT+P to unparent it before deleting the group.

Now to the exporting!

You may have to assign a texture to the mesh before you export the .dae, otherwise your model could be invisible in the level editor even though it has a .mat applied (and even though it is visible in Model Editor!). A quick way to test if this will be the case is to click on the button with the two cogwheels at the bottom of the model editor to enter test mode. This issue is also probably what's causing the error message from your first post.

It doesn't need to be the same texture you want to have on the mesh later - any texture will do, just make sure you put it in the same folder as the mesh. It has something to do with the way Open Collada exports stuff...it does weird things if the mesh doesn't have a texture assigned on export.

Just need to get the texture lined up appropriately.

By lined up, I assume you mean the uv layout? You'll have to do that in Maya and re-export afterwards. Assign the texture to your mesh, then go to Window>UV Editor. Now unwrap your model and arrange the uv shells so that they line up properly.
There are several workflows for how to do this exactly, it depends on what kind of model you have. It would really take too long to explain here and its easier to learn if you see it in a video anyway. This one might help for example.