I think that #1 and #2 of your questions would be to use leaders and enders. These are small scraps of fabric, maybe 2" square that you start off with. You start sewing on a leader, sew off, sew a few stitches "in the air" then sew your block. You can chain sew as many blocks as you have ready, then at the end sew a few stitches onto an ender. Leave this last piece in the machine and clip the thread between it and your last block. The ender is now your leader for the next group of blocks. Snip the stitches between your blocks to separate.
Don't back stitch your blocks.
3. You can try using a block of post it notes positioned at the appropriate spot to keep your stitching straight. A sticky from a Command hook can also be used.
4. Don't know how old your machine is, but I've never seen a machine made past the 50's that didn't automatically stop winding the bobbin at the appropriate time.