To answer as many of these questions as I can from my own experience and understanding (and I guess preference as far as the forum itself goes).
Threads: As many as you need. I know Antonio suggested otherwise, but I AM IN CONTROL!!!!! (mua ha ha ha ha ....).
Seriously, my thinking is that a few, focused threads on specific topics is better than mushy threads that sort of cover everything. In this way, everyone can go right to the topic in order to ask or get answered any question they have without have to search through a long string of posts in one huge thread. I will start a few that I think might be useful, and we can decide if it works or not.
Photos: You don't have to photograph your entire collection. The first thing I did was look through my collection and physically pull out and put aside the pieces that I thought were nice and would be good for the section. Then to the extent I didn't have some picture of it already, I took a quick photo. It doesn't have to be a Picasso or Pulitzer Prize caliber picture, but something clear enough to let the other's see what it is & how it looks. The high quality pictures for the catalogue will be taken by the Museum once the final pieces arrive in Macao.
Time away from home: I am allowing six months in my own mind, between the time before the show for processing, the three months exhibition itself, and some time to pack up and ship back after the show. Antonio I am sure will give a better answer than that, though.
Decision making: That is most of what will be done here on the Forum. I have no idea personally about what to put in and what not to, but I can help with suggestions just based on what I know of the exhibition hall layout (which I have seen in person), and what I have learned while doing my own section. I have already given a few just about sort of the mental approach you should all take. I do highly recommend that one or two people make the first broad cut once everything is on the table. What I did at first was to take everything we had and group stuff by similarity, literally moving photos around in a PowerPoint file. Then we looked them over and decided which best showed a particular style or feature or historic period. It also helped us notice gaps. So maybe one person at first can sit and take all the barongs offered and put them together, all the kris, etc. I did this by printing out the pictures from our working page and laying them out on the floor in stacks, then going back and re-grouping the pictures on the computer. We had fewer pieces than you do, but I suggest organizing them in groups as a list with their ID numbers, and forwarding that to Antonio and I, who will then physically group them on the web (assuming that is what you all want).
Posting some pictures here as suggestions by whoever does this first step is a good idea, as well as posting representatives of the proposed groups. Whatever you think will work, and we can adjust as we go along.
Irreplacable pieces Rick said it all. Everything in this exhibition will be irreplaceable, either literally or sentimentally. We do need to have a certain level of trust in the process. There are things that are priceless to the point where placing an insurance value on them, no matter how high, is meaningless. I have said many times that based on direct personal interviews and inspections of the Museum operations & facilities, that Antonio, the Museum, and the Museum staff have my 100% confidence in every respect. Of course, that opinion is worth as much as my credibility is with you, but I hope I have at least a little.
If you don't know, I am a 42 year-old lawyer who has not only lived abroad, but have had my share of getting screwed, this in addition to spending 12+ years litigating against other wily lawyers, which sharpens your BS detecter, your paranoia, and your ability not to be taken for a ride. So, I know what to look for and what to look out for.
I hope this helps. I am sure others have more to add. I'll go start some basic threads, now.