Thanks for re-posting your questions here.
1. No, ttl modulation is not required. You can specify in the settings of lasershark_displayimage if ttl should be used (monochrome), if only one analog color should be used (greyscale), or if all channels should be used (rgb)
2. You cannot make the galvo angle range smaller via the software. If you need this to occur you should scale down the image from being 4096 bits wide to your desired width.
3. OpenLase has an .ild player called playilda. This is present in the tools directory. It is limited but will play some ild files.
If you run lasershark_displayimage with the -h flag (don't pipe this output to lasershark_stdin of course). you can see what options are available for tweaking.
Hope that helps!