Isometric games : 3d character animation test

In the past week I produced a simple animation to test with an isometric style game. My goal is replace my static characters in Metalwarriors with those that includes animations.
But I'm not really sure to do this mainly with for these reasons...
- creating animations for each character means spending lot of time: and how many actions I will do animate? Only a simple walk, or other actions, as fight, death, and so on? Creating each action means create "n" frames for 4 different directions.
- how many Kb these animations will take? This can be really slow downloading times...

However, some descriptions about this simple animation...
I created this animation with Lightwave 3d starting from a 3d character, created as described in my 3d Tutorial: Modeling your first Anime Robot in 3d (italian translation here), then I animated with a simple walk cycle, rendered as separated frames in BMP file format. For a better result, I choose a 17 frames sequence (see preview).
Creating characters in 3d also for 2d bitmap based games has a great advantage: after created animation cycles for a single character, I can create the same cycles for all other characters, simply substituing the 3d models. Additionally, I can create separate animation frames and, by saving in 32bit color depth, I can have each single frame with a transparent background. This can be an advantage for test purposes, to check the optimal size of my bitmaps frames, to have good animations but not a wasting movieclips sizes...

After this process, I can import my bitmap sequences directly into Adobe Flash (name each frame as "animationCyle_001.bmp", "animationCyle_002.bmp"): Flash converts the frame sequence directly into the timeline, each bitmap into a separate frame.
So I can create a single movieclip for my character, and naming each first frame of each sequence into Flash timeline, I can access and play my animation cycles via actionscript.