I can help you with the first one. It is either made by M & H Schrenkeisen or John Jelliff.
The first image below is your chair incisings imposed over a chair in the Bybee Collection (attributed to Schrenkeisen). I put some yellow color in them since it has worn away over the years on your chair. The similarities are fairly numerous, down to the bellflowers and arm carving. See another one at the Met, here
The next image is of a chair owned by the Newark Musem that shows the curved arm support such as the one on your chair. The incising is again like yours (picture 3). The museum attributes it to John Jelliff.
More on this conundrum here