1) No. And for clarification – this used to be the case on OS versions prior to 1.60, with regard to the internal resolution. That restriction has been successfully removed.
2) Not currently. On Octopus you can, using PgmChange, but not on Nemo. Reason is, we are looking for a better way to do it, which will find its way into both machines.
3) Do you mean a full machine state? That will depend on the number of written pages (i.e. non-blank pages) contained. Transmiting a page takes on the order of 5 seconds, and transmitting the global settings takes on the order of 10 seconds. Depends on your MIDI interface settings, too.
On a side note, you do not have to stop the sequencer for the sysex intake, if that matters in any way to your setup.
4) Similar to 3 – it depends really on the number of pages writen. A page is 10K and the global data is 16K.