You answered my questions well and completely, so I should at least attempt to answer your two questions, based on a little evidence and my reading about Missouri during this period.

a. Why was Ebenezer Corbet reduced to virtual poverty? I really don't know for certain, but his family connections certainly hurt his ability to contract for the U.S. Gov't, and, as you will see, he had to pay a large bond to keep his freedom as a secessionist suspect. I think that stopped his membership in the St. Louis area EMM, too, but I have no documentation that told me that.

b. Did his own indiscretions or those of his relatives result in Corbet's having to yield title to his large land holdings in Osage County? I really don't know the specifics, but I imagine that was the case.

Now, some of my findings that lend themselve to the above answers:

You were correct that Robert M. Renick is mentioned strongly connected to the Knights of the Golden Circle in the "Official Records of the War of the Rebellion" series 2, vol. 7, in three places as indicated in the index of that volume.

Joanne Chiles Eakin's landmark 1995 "Missouri POWs" (the actual title is three lines long) taken from the National Archives and Records Administration southern prisoners of war files gives these entries in St. Louis area military prison ledgers as kept by the Union military:

William Corbett citizen of Osage County arrested there 15 September 1862, sent to Gratiot Street Military Prison in St. Louis, and released 27 January 1863 on his oath and bond that he would not support secessionist activities and instead support the U.S. Gov't thereafter. (Is this a relative of your Ebenezer A. Corbet? The name in the place tells me it might be.) The amount of the bond is not recorded on this source, but it could have been in the thousands.

William H. or J. Clendenen citizen of St. Louis arrested there 9 April 1864 and sent to Myrtle Street Prison in downtown St. Louis from which he was released 14 May 1864 having given oath and bond of $10,000 as a guarantee of future non-secessionist good behavior.

Robert M. Renick citizen of St. Louis arrested there 6 March 1864 and sent to Myrtle Street Prison in downtown St. Louis from which he was released 15 May 1864 on his oath and bond of $3,000.

I should add that Myrtle Street Prison was the former Lynch's Slave Market and most of the lockup was underground and a dreary place indeed. I assume the Union military sent these wealthy businessmen there to intimidate them, which I am sure it did. During 1864 Myrtle Street Prison was mostly used for what we now call "political prisoners" including a small number of women convicted of giving aid to the enemy, and Union military felons including deserters. It was more a place of punishment because of the environment than merely a place to humanely house prisoners. The Union military enjoyed their little joke of caging southerners in a slave market, but the place was really not fit to be a military prison, and several Union medical inspectors told their superiors so.

Did you read between the lines to catch my remarks about punishing enemies of the Union? That is relevant to your two questions above. That reaction to secession grew in popularity until by the end of the war politicians who espoused the "radical" solution to ending the rebellion were in power in Missouri and intent on punishing those who dragged the country into war and all the loss of life, suffering, and the harm to economic development. Those are their words, not mine. The "moderates" such as Lincoln and the earlier wartime MO provisional governors lost their power to the radicals in Missouri by 1864 and into the postwar era. That is why so many former Confederates and southerners in the "Show Me" state left Missouri after the war for Mexico, Texas, and other places with less vindictive citizens.

You Tillaye ancestors seemed to have changed their name by mutual agreement by the 1860s to "Tilley" and the 1860 Missouri census shows several clans of them in St. Louis and the counties near the city. I don't know if all the Tilley families in the census are related to the Tillaye families you mentioned. The census shows a number of these were wealthy and originated from KY, SC, TN, and IL. Some Tilley households were far from St. Louis in Pulaski, Harrison, Clinton, and Ralls Counties. The Tilley family in Pulaski County was literally destroyed by the war and several members were murdered or executed, and have become part of folklore there. I found none in Osage County, but nearby in Franklin County was a young household from Illinois. His is the only one that does not originate from a southern state. The MO Secretary of State's Office website's online Civil War military service records shows a number of Talley men involved in supporting the Union and a few supporting the southern cause.

That's about all I can add to what you have already accumulated. I wish you well in your search for answers.

Bruce