I'll second your point 2, and add to it. For me, some recipients are receiving the resulting messages out of order, or not at all. Even if they receive them all, they are most definitely not being reassembled into a single message on the recipient's end.
I understand there are 4.4.x API changes, but did they leave no way to send messages correctly? I started seeing this problem on CM11S ported to an LG G2 and continue to see it on CM 11 M9.
For the record, I'm having messages split into 67 character chunks, which means it's probably using unicode characters somehow rather than 7-bit ascii. That would be fine it the messages were correctly reassembled on the other end, but they aren't.