some times they do a stretch and sweep which means if your cervix is favourable it can cause natural labour with me i had 2 s&s's with my last two and they brought them on within 4 hrs or less..
the bleeding is natural too just keep an eye for your mucus plug or a big gush of water..
is this your first?
the tightenings can be a pretend warm up for things to come, you may go into labour by then and have it before then
babies can always change positions and engage out of no where lol they are funny little things they never do anything till their ready..
GL keep us updated