Since you've already got more money into the gun that it's worth, I see no reason to stop now; for if you did, your investment to date would be worth even less. As to the fore iron hanger lug, they do occasionally pop loose (I have a LeFever with that same problem as I write); if the ribs remain tight on either side of the lug, a double gunsmith can resolder the lug and you're back in business (although the repair could damage barrel blue around the repaired area; but with the added beavertail, it should not be noticeable with the gun assembled). Since this gun had undergone a certain amount of "gunsmithing" prior to your acquisition, were the gun were mine I would want the barrels thoroughly inspected by a professional; for if those barrels had been re-blued at some time, and the process was a "hot blue" and the bluing salts used in that process not correctly neutralized, you will have additional problems down the road as the chemicals used in the hot blue process will dissolve the solf rib solder in a set of vintage gun barrels. As to the top lever, that sounds like a missing or weak hold open pin spring (the spring pushes a pin upwards to engage the top lever with the gun broken open; and, when the barrels are closed, depressed by the rib extension so that the rotary bolt can engage and lock the gun closed); this is a very simple fix for a gunsmith. As to the safety, something is probably misaligned; a common occurence when reassembling Smith guns. But if you are smart, have a gunsmith convert the gun from a 3-position to a 2-position safety; the 3-postion safety is awkward and will cost you missed targets/birds. Also, because it is awkward, it is dangerous; and many accidents have resulted from someone thinking he had his 3-postion safety in the "safe" mode when in fact it was inadverdantly placed in a fire position.
Finally, I did not appreciate the tone of this remark by Gregg; "I knew he would post even if what he said was meaningless" (not an exact quote, but close), and I assume it was directed at David W. I personally appreciate the contributions of David W (and many others) to this forum; as well as his time and effort to assist posters with questions and problems. Regular readers will note that SGT posts are infrequent nowadays at best, and that is a direct result of the good work and information being posted by David W and others here; for the simple fact is that I'm not really necessary anymore. Because I well understand the time and effort that must be invested in every thoughtful and reasoned response, I personally found this kind of remark most offensive and absolutely unnecessary. In my opinion when someone has only garbage to contribute, he should keep his mouth shut and his hands away from the keyboard.