Trouble with casting a complicated print

One way or another, you're going to have to cut the mold to make the casting/original removable. In other words, you're going to have seams but they can still be part of the mold so you won't have to worry about losing pieces of the mold. Unless you just want the mold itself and it won't be used for casting afterwards - the mold itself is only a "display piece" like those clear globe with an etched design inside it.

If you want the mold itself to be a display piece (which it sounds like from the description) I would actually make two molds - the first one of the figure you have there and the second mold being the final mold. The first mold gives you the shape to be molded and you cast something that goes from a warm liquid for pouring to solid after cooling - like making hard candy. Then you use that hard candy casting to make the second mold (with a small pour hole on the bottom). When the mold is cured and fully set, you just warm it up and the hard candy will pour right out of the pour hole on the bottom. And if you use a hard candy casting, I would rinse it out a bit too so that the inside isn't sticky.

Now if it's not going to be a display piece, you can do a one piece mold and just carefully cut inner seams to be able to remove the casting. But you will need a dedicated mold box to hold the shape tightly and the seams won't show as much. And you could use a clear mold box so you can still see inside the mold. But that middle piece that isn't attached, I would make it attached to some part of the mold, I don't like pieces that can move around inside a mold myself - it's too easy for the piece to move where I don't want it to and ruin the casting. You can also do the mold like you're going to do a two piece mold with zig-zag inner seams but don't cut all the way through. Something like the picture below.

 (Sorry to draw all over your picture)

 The red boxy looking lines are the mold box and the ones inside are the seams. The ones on the legs are the seams you cut going straight down to the tabletop.

I hope this helps some. I've had molds with complex shapes and very thin pieces with many angles/undercuts and that's what I've done with the molds. Yours is a more solid, thicker piece so it should be easier than some of the molds I've done.