I also do not know how this style is called, but here is another great sample video of this style:
http://youtu.be/N56r-Uxr5Tk?t=25s
I guess you can copy this style if you are a skilled 2D and 3D artist. It seems that moving/animated objects are 3D rendered meshes with painted textures and the foreground and background are just flat painted layers.

You are looking for a combination of art, animation, and "camera" work. The 2d artwork is by far the most impressive part of those videos. Requiring excellent drawing skills. The animation and camera work is very simple and could be learned quickly.

It looks like 2d images made on different layers being animated with simulated camera work. If you wanted to make something similar you would need to get/create artwork and learn basic animation and camera work.

Danimal, if you wish to mimick this style closely, it's 2D artwork first, later animated in AfterEffects or similar animation/special effects software. Animation is the easier part here, getting right 2D assets (static and animated) is much more laborious. There's a similar style, where you put handpainted and scanned textures onto simplistic 3D models, but the final look is not quite the same - possibly like the first example you've given.

Keep us updated!

Cheers!

Qx beat me to it. Certain parts like waving hair is adobe after effects and layering. 

This course shows after effects magic. THis is the final animation.

http://cgcookie.com/concept/lessons/1-the-final-animated-splash-screen/

This is the course showing how its done.

https://cgcookie.com/concept/cgc-courses/9585/

if all you wanted was a stock image from a 3d model im sure any of the tutorials could be modified for that. sorry if this isnt what you wanted. maybe be a little more specific

there is this

http://sertaogames.com/2013/01/30/isometric-tilesets-from-3d-modeling/

also this

http://flarerpg.org/tutorials/isometric_tiles/

Regarding software choices and pricing, moving things by itself is a task Synfig (as well as Blender - pity, but GAP doesn't seem to be developed enough) is well capable of, you just have to be patient, persistent, stubborn and ready to go through a crash every 30 minutes or so for (more or less) a week for every two minutes of a finished animation. With more bling-bling in your production, chances for Synfig to tackle it are getting closer to none, time spent - longer and frustration levels higher. Without all the lightning effects, dust in the air, dynamic glows you're straiht in the 90-s with bare sprite animation. And there will be no bling-bling to cover up any flaws in the 2D part - either it will look good and stand by itself or not.

AfterEffects is expensive, but it gets the job done several times quicker, at least from my experience with simplistic projects. If monthly subscription of Creative Cloud service is an option, prices start at 37 Euros/month, so one or two person-hours worth of expert's time.

I don't know if it's a standard term or not, but David Rosen from Wolfire Games calls this style parallax animation.  Parallax is the effect of how the view of something changes depending on how the point of view shifts -- when the camera moves, things that are far away move less than things that are closer.  Incidentally, this is important in astronomy for figuring out distances of far-away objects.  Aubrey from Wolfire demonstrates what he calls his "2d/3d animation" style here: http://blog.wolfire.com/2012/11/Art-Asset-Overview-38

For getting an image like that with a blur effect around the edge from a 3D model, here's what I would do.

First, to get the image from a 3D model, I'd render it in Blender with the output set as a PNG file with RGBA -- this means it supports the alpha transparency channel, instead of filling it in with a black/blue/whatever background.

Next, I'd open that image in GIMP, ctrl+A to select everything, use the color picker or wand to un-select the transparent (checkerboard) background, then use Select > Border from the menu, choose how many pixels thick I want the blurred part to be and whether I want it feathered or not (which means the blur effect we're going to use would be applied more to the core of the selection and less on the outer borders), play with the previous step to get the right thickness, then choose Filters > Blur from the menu, and play around with the options I see there until I get the desired outcome.  If the blur effects don't get the desired effect, you could use the Smudge tool to do it manually.

Using it in dungeons reminds me of some of the Might & Magic games, where you're in a 3D environment but the NPCs and many environmental objects (trees, etc.) are all 2D sprites.  The environmental objects are set to constantly face the camera (this is called billboarding), while the NPCs have front, side, and back facings.  You can see this in effect here: https://www.youtube.com/watch?v=2_GKkluZD28

In case that's what you're going for.

Interesting Blender add-on looks like it could be useful for this kind of thing: Point Convert 3D

https://www.youtube.com/watch?v=yGPLjeaLFEw

Isn't It basically just Like a multiplane Camera with a static image?

https://www.youtube.com/watch?v=YdHTlUGN1zw