I did some tests whit the bogs myself, they do work whit a 1 block wide gap and the turbary can harvest up to three bogs (one on the same level of the turbary and the other two above/below that one)
I can confirm that. Also, I turned off the peat engines and turned them on again to see if interrupting power has any effect, it doesn't look like it though as they continued working just fine after turning on the power again. Maybe they can bug out or something, but I'm assuming under normal conditions it won't be an issue if power drops or is cut temporarily.
I do advice to activate them from bottom to top though, the bottom one did seem to have trouble starting when the top 2 Bogs were already working.
Anyway that's good news for my Peat farms, it means I just have to move 1 and probably restart the other 2 in the right order to get everything up and running