What The Doc sez ↑↑↑; first and foremost you have to make absolutely sure all of the fasteners are out. Then you sometimes will have to pry a little to get the two dowel pins out. Fotos looks like that part is done, but double check. And finally, you have to be sure you aren't physically in contact with something in the engine compartment that is keeping you from moving the engine forward. There just ain't anything else. Except the clutch attached to the engine/flywheel, and the transmission input shaft, keyed to the splines of the clutch friction plate. This is supposed to be a sliding engagement, but sometimes it don' slide so good.
Fluff, don't throw in the towel; you are almost there. Check to be sure the engine is hanging free from your shop crane, and if it is, slide underneath with 10mm and 12mm combo wrenches, pull the cover plate, and remove all six pressure plate bolts. Once they are all out, you should be able to spin the tranny by hand (no longer engaging the engine via the clutch).
Man, if it doesn't come apart then, you need an exorcist or something :-D.
(Edit) And it seems like I saw this mentioned above, but once again: Use your floor jack, and a chunk of 2X4 to gently lift the front of the transmission, and lower the engine a bit until the gap between the cases is more or less even all of the way around. In your instance, gently pull them together with one of the bolts if necessary. Then start at the top center, where you are currently having issues, and use something like a wood chisel with a light hammer and tap it into the gap between the cases there. If it still doesn't move . . . Some Dynamite maybe?