Not sure about the linea, because I never got one. As for the moving into position, my son was head down basically my entire pregnancy. Every time I went to the midwife or had an ultrasound, his head was down. Even with that, he failed to engage even when I made it to 10cm, and I wound up with a c-section. So, to me, being head down doesn't mean too much.
My daughter was breech until close to 39 weeks. She came at 40 weeks, 1 day.
He has been transverse most of my pregnancy. But the Dr said it was a weird position that he doesn't see very often. He delivers a whole bunch of babies well over 400 a year. So it's been a big movement for the baby to flip. I have 36 days till full term.
I went to my Dr and made it a point to ask about this line. He said it's odd for me not to have one. He said all women get some degree of the line. Apparently mine is very very faint and very very low. In an area that I can't just look down and see anymore and in normal household lighting it seems not to be here. Even hubby had to have Dr point it out b/c he hasn't been able to see a line. Just thought I'd follow up on this.