My Jags grew from 4 inches to 8 inches in a couple of months before slowing down in growth. And these guys are thick for their size just like others in their family such as Gulpers and Trachycorystes. They also get to about 10 inches SL so that's without tail which is a decent sized fish when you consider how wide they get. I believe the biggest Poly I've had was a Lap female around 14 inches and her head was no where near as big as my Oncinus. Just over half as wide as my Oncinus despite being almost twice his length.
They are shy as moe said but IME the more you have of them the more confident they seem to be. For instance I had 3 Oncinus with 4 Trahcycorystes and 2 Gulpers and they used to come out quite a bit following the Gulpers and Trachys looking for food. I lost one Gulper and sold the other and wound up selling 2 of my Trachys and noticed a change in all the driftwood cats behavior. They all became more secretive. I have a feeling in nature Oncinus might live together in large communities in large pieces of driftwood. And therefore are far more confident the larger the group they are kept in.
You might be right as I said I have no personal experience with Bolts. I was going off of what Planetcatfish says in their article and profile. Perhaps I interpreted more aggression then was actually implied.
I never kept my Jags with large cichlids so you maybe right on that as well. I just know that my Jags acted very differently when kept with other driftwood cats. And in such a group I found them as aggressive when feeding as my Trachys as such they weren't easily bullied by the other cats at least. My 3 Jags however always fed with the lights on. The only thing I couldn't get them to do was eat at the surface like my Trachys and Gulpers. And I think the other fish I had at the time where those two Oscars I always mention as being one of the fish I most regret selling, a Silver Aro and a Indo Dat. However those O's where real easy going unlike some of the wild O's I have now like my Rubrocellatus which are fairly aggressive.
I'm with moe on the Marm, they are said to be skittish in tanks where their whiskers hit both sides and their whiskers are very long.
I believe in such a large tank the bolt would be okay with the platyrhynchos, centro and ornatus. Only the bolts hide would be off limits and during feedings I thought he might be aggressive but I also figured the cats mentioned wouldn't easily be intimidated into not eating.