Nice shots! A few suggestions … (natch)
(1) There’s a little light-play on the lower edges of the lower windows that seems a little unnatural.
(2) When shooting inside of a cathedral, a professional photographer must resort to a lot of hidden lights in order to bring “light into the darkness.” You don’t want to be without detail in the shadows, such as in the lower left side of this image. Whether the light source is “practical” (visible) or hidden, it is needed. It’s also nice when you inject a few warm colors into some of that light. I personally don’t feel that you need to have any “explanations” whatsoever for this additional light. To me, it is perfectly acceptable to use the “ambient light” feature to control general contrast.
(3) The last two shots definitely went the wrong way: one is much too dark, and the other has a muddy “wash” all over it. Neither of these helps the picture.
(4) The circular window in the top of the tall window at the altar of the church appears quite pixelated, because the ribs that form this detail are small at this distance and there simply isn’t a lot of screen-resolution with which to depict it. I don’t really think that the window was improved from the original by this change.
(5) Even in the very first image, I had the impression of a cathedral church… nice basic lighting, color’s good, seeing cloud details outside is a nice touch, good overall illumination of shadows except the lower floors. In other words, a really nice feel to it. I would therefore be very sparing in what details I chose to add to this picture. I think it’ll work very well as a rather austere image.
(6) Always pay close attention to the contrast. In your original shot you had much better control on this vital aspect of the image than is evidenced by the later revisions. Here you have brilliant sunlight pouring into a church … but throughout that church there are (almost) no areas that are under-exposed. The light fills the church and suffuses through it. That’s part of the reason why the church does not seem gloomy. Although the brilliant sunlight is pouring onto the stone floor, that light is being offset by reflected light from the inside of the church, including the distinctly-blue light that pours down from the sky from everywhere but the direction of the sun itself.