1 (Transition): Depends on what you want. Personally, in A World Made of Glass' project file, I would have two bars before the actual song plays of that same bell pattern, which will get left out unused in the final track as it is meant for the transition. I would export these two bars separate, and then add it into the end of Journey to the Forgotten Realm. After which, I would apply a low-pass filter automation (starting low) to made it naturally fade into the next song. I could go on and on about seamlessness in music soundtrack composition, but I can probably teach that later as it is quite complex. Feel free to do whatever you like with the effect stuff, it's your music!
2 (Glass Bell Sharpness): In order to make the glass bells less sharp, you can apply a Transient Shaper and turn the attack a little down. If you don't have one, Kilohearts has an amazing free suite of effect plugins and it includes a Transient Shaper along with so many more useful effects.
3 (Glitchiness): In both of those two songs, the glitching could be caused by some weird export settings. I'm not entirely sure as this has never happened to me, but I have a couple hunches. Do you know if it was stuttering in your DAW or after export? If it was stuttering in your DAW, then it might be a problematic plugin (which I highly doubt considering I only hear a LABS choir patch in Tower of the Heavens). If it wasn't, then it could be mismatched project to export sample rates, or your audio buffer is too low.
4 (Ostinatos): An ostinato is a phrase of music that gets repeated persistently across a piece of music.
Anyways, that's all for now. Thanks Darth_Majora!