I'm new to creating themes and have a lot of questions (Zelda Item Screen theme)

[Tamoketh]

Hello!

So I want to make a theme for myself based on Zelda games, Link to the Past specifically. If you just want to read the questions, they are at the end of the post.

The main idea is that, instead of having the carousel scrolling through the systems as normal, all systems (with roms) would be displayed and a selection cursor would move through the systems. For reference, this is what I'm going off of:

https://legendsoflocalization.com/wp-content/uploads/2018/06/snes2.png

So the main ITEM area taking up the top-left corner of the screen would be showing icons for all the systems that have roms for them. Since this is mostly for personal use, having a "limit" of 20 icons shown won't be a problem. Instead of scrolling the carousel of systems, I'd have a cursor that would move though the list. The top-right window in green would show the system's name. The two yellow windows on the right and bottom-right would show 2 screenshots of games on the system. The red window along the bottom would have system information like release date, sales, etc. The background showing a blurred 3rd screenshot.

So, there are probably many ways I could do this if I had more experience with how EmulationStation/RetroPie works, but here's what I'm planning on doing. Showing the screenshots, system information and system name should be easy enough. I'll have the carousel be hidden and just have the system icons loaded directly from the main XML. Then, I'll move the cursor image over whatever the currently selected system is. Even if it still moves the carousel, I'll arrange the icons in the same order as what the carousel would show. You won't be able to move the cursor in all 4 directions, but at least it'll move as expected left-right.

So, my list of questions:

• Is there an easier method than my planned work-around? Instead of having a fake cursor that moves around governed by the theme.xml for each system, is there an easier/simpler way to do the desired effect?
• Despite the carousel only be horizontal or vertical, is there a way to have my planned item selection allow moving in 4 directions? Since all it would do is use the default carousel, but have it be hidden to only show my item selection, I almost assume this isn't possible. If that's the case, is there a way to have it jump to specific systems? Like have variables that track it's position and I could know if I'm on the NES and press down, that it would jump to the SNES that happens to be below it?
• How would I go about hiding the Carousel? Is there a "visible" or "hidden" tag I can assign to it? Do I have to just move it off screen or set it's Z position to be under the background so it's blocked off?
• If something is set in the main xml and in the theme.xml files, which takes priority? EX: I set the POS of my cursor in the main xml as a default like 0.15 0.15, then in the theme.xml of the NES, SNES and GBA set the POS to correspond to their system icons (EX: 0.15 0.15 for NES, 0.2 0.2 for SNES and 0.25 0.25 for GBA). Is the POS from the main xml always used and the cursor would not move? Would it take the POS in the theme.xml of the system I'm currently selecting (EX: SNES), and if I scrolled to the NES it would then use the NES's theme.xml POS?
• If a system doesn't have any ROMs and would normally be hidden from the carousel, is there anything from its theme.xml that would get loaded? So, if I continue the above example and had the PSX with no ROMs available, if the theme.xml for the PSX added images or changed variables, would it ever get read/loaded? Or it would only be loaded/seen if I added a PSX ROM?