No sir, I'm just gathering intel and trying to make a calculated decision is all..based on those more wise with carpentry matters than I.
Re: The Triangle...I spoke to the fella who pulled off the miter corner sink as seen in the previously posted link. He said it's holding up great after 6 years or so, with attention to water and cleanliness of course. Aside from the sink sitting over a joint and being non-ideal, what do you think?
I'll just qualify all of what I am going to say by establishing, I hate work that looks like the homeowner did it. It is either pro quality in appearance, or don't do it.
The only way to do that install, and have it look right, is the way I have already stated. Anything else will look like a hack job IMO.
The issue with the triangle, above and beyond looking like an after thought, is that the butcher block will have the top edge just slightly eased. Notice it is not sharp? Now you are going to try to stick a piece that you have cut on there, it will have a slight gap on the surface because that edge has been eased. Sure epoxy will likely fill it, still going to look bad IMO.
I like the idea of using epoxy for the joint, the West system although pricey, is great stuff, I use it a lot, make sure you get the pumps, so easy to mix that way.
Biscuits will do absolutely nothing for you from a strength perspective, at best they will help align but even then not so much. They depend on the moisture in the wood glue to expand, very unlikely epoxy will have the same effect.
Counter top bolts are mandatory for any joint IMO.
So you are caught between will it work, and will it look right. You have to decide as you are going to live with it. I couldn't live with it the way you are describing. But then for me I wouldn't consider butcher block tops at all, but that is another discussion.