What parts does the Xbox One X have in common with the One S?

I'm considering buying an Xbox One X--if I find one in good condition--to replace my Xbox One S. I'd like to know what parts, if any, the One S and One X have in common, so that if I buy a One X and need to replace any of its parts, I know what parts I can source from my One S.

Here's what I've gathered so far about the One X's parts, in comparison with the One S' parts.

I don't know whether the motherboard, CPU, and GPU are integrated into a single board, which I think would be called an SiP (system in package); regardless, they are obviously different from the ones in the Xbox One S. Maybe a few motherboard parts might be the same between the two different SiPs/motherboards/CPUs/GPUs, but I assume that most of them are different, and are higher-specced in the Xbox One X.

The power supply has a different model number.

The fan assembly might be completely different from the One S' fan, heat sink, and chassis. iFixIt lists the One X's fan assembly as a single unit and the One S' fan, heat sink, and chassis as three separate parts. For the record, I know that a chassis is for more than cooling.

The hard drive might be different, but it is probably still a 2.5" SATA HDD, and so a One S' hard drive probably works in a One X, and vice-versa, along with any off-the-shelf 2.5" SATA HDD that has been formatted and partitioned appropriately for use in an Xbox One.

The hard drive bracket might not exist in the One S, but if that's just a piece of plastic, then I'm not concerned about it.

I'm not concerned about differences between the One X's and One S's top brackets and differences between their bottom brackets, because I'd never replace a One X' black exterior with my One S' white exterior, because I prefer black, but the One S wasn't available in black when I bought it, which was when it had just been released.

It is hard to tell if the optical drive's model number is the same.

The above notes come from a cursory comparison of the replacement parts that iFixIt lists for sale for each of these two consoles, and from my limited research into replacing my One S' internal HDD with an SSD. Brief Internet searches for [what parts do the "Xbox One" X and S share] and ["Xbox One" X and S same parts] and cursory skims of the query results did not reveal any useful information.