MoRLOK

You're welcome.
It is something that everyone needs to get used to, unless eventually Serif decides to make a change. Many users have complained.
Hand-alignment should not normally be needed, just setting the options I mentioned to ensure that initially your objects are properly aligned.

Make sure that the affected objects have their X/Y coordinates (see the Transform panel) that are integer pixel values, and their Height and Width are integer pixel values. Note that you may need to increase the number of decimal places displayed for pixel measurements, using Preferences, User Interface.
It is easiest, usually, to ensure this by setting Force Pixel Alignment in the Snapping options, and by setting Move by Whole Pixels off.
Thanks for the example. If you look at the placement of the layer "back ground V3" you will see:

If you nudge it to X=590 and Y=1388 I think you will resolve your problem.

BTW the flash format is pretty dead nowadays and widely treated as being the root of all evil! - So you better take actually the replacing HTML5 Canvas or WebGL route here instead, also to being more on the secure and up-to-date side here.
 
Take a view of the existing game engines and also think before about maybe possible platform and device cross-platform portability for your game. There are runtime and dev environments like for example Unity, which can overall ease this process and which support to work with a wide range of assets.

I think that depends on the developer and how he is gonna use the images that you are generating. Flash/AnimateCC it self is an animation tool so if the programmer is used to animate UI elements you will need to import the assets from affinity there. You could check how "Samrost 1" of Amanita Design was made... it has a lot of raster images working on the game. I know they generated several atlas for the sprites but exactly how they did that I'm not sure.
If I would need to animate a button I would simply create 3 states... 1 Idle. 2 Active. 3. Support image... and support image being some extra border or glow that the programmer could give some interesting effect as bloom or ease-out for example.

1) export each element as a SVG from Designer
2) import each SVG element into Flash. You will have to convert the elements to graphic symbols and/or movieclips in Flash.
3) if animated elements are required, use the moviclips/graphic symbols to animate things. You may have to create additional nested movieclips to animate sub-elements, if needed.
4) hand final Flash file with animations to developer.
 
Don't forget to organize the assets nicely in Flash's library, of course. Confer with the developer whether he/she must have movieclips, graphic symbols, etc. to work with during development.
 
Most artists who I know work in a separate illustration tool, and import the static assets into Flash for animation, then hand over the file(s) to the developer.