Surlair, welcome to the forum!
I love your experiment but I don't see any protocorms. The green bits are probably just algae.
Not too long ago I conducted an experiment that was nearly identical to your own...
The big green things aren't orchids... they are Rhipsalis. If you look closely you can see very small, round, green things.
Those are the orchids. I sowed them at the same time that I sowed the Rhispalis.
The only real difference between our experiments is that I used reed-stem Epidendrum seeds. My theory is that, unlike most orchid seeds, the reed seeds have enough nutrients to germinate on their own.
Here's what they look like when they are more mature (different experiment)...
Towards the bottom of pic you can see a "big" green orchid leaf.
My friend had gone to Cambodia, or Laos, or Vietnam and she brought back a small "vine". It turned out to be Pyrrosia piloselloides. I stuck it in a pot in a zip lock bag and sprinkled Vanda orchid seeds on top. I guessed that maybe the fern harbored the helper fungus.
Maybe a month afterwards I was very excited to see a protocorm developing. Eventually it put out a leaf, then another leaf, and then a third. Then it put out a side shoot. Eh? A side shoot? The side shoot put out leaves... and then it put out a side shoot. Eventually I became certain that it was definitely not a monopodial orchid.
I was pretty sure that I had sowed Vanda seeds.... but maybe I made a mistake? Now the seedling is looking a lot like Dendrobium crumenatum... which I don't have... and neither does my friend. So I guess the seed was already on the fern when my friend brought it with her.
When the Dendrobium was still pretty small I sowed a bunch of different seeds on the medium. Most of the seeds that germinated were just the reed Epis.
From my perspective, it would be a very important project to try and create great
reed-Epi hybrids that can also be easily grown from seed. The orchid hobby would immensely benefit if there was a huge variety of awesome orchids that could be grown from seed as easily as Rhipsalis, Begonias, Gesneraids and pretty much all the other plants.
For some more info and a couple more pictures here's my blog entry...
Growing Orchids From Seed Is Easy!