Bootmii itself can be updated by running the prepare sd card function from the hackmii installer (or by downloading the bootmii sd files, but the hosted files aren't the latest version, but new enough that it doesn't really matter in practice)...
I'm not very experienced with Swiss, but you can region change using modmii after first ensuring your softmods are up to date by running the main Modmii Wizard or its syscheck updater wizard
Any region changer modmii edition may allow u to...
Did you watch the part of the video that says "where to start?"
... Run modmii on a windows pc
Start the main Modmii wizard and tell it your wii is a virgin even if it's isn't, follow the prompts
Or drag and drop your syscheck.csv onto...
Could be, but base 56 AND 57 cios will play the vast majority of games so I don't think it's very likely.
U said earlier that disk based games aren't working. Have u tested just 1 or many? If just 1, could be a damaged disk, if multiple, that...
Your IOS249 should be base 56, curre tly u have the same cios installed to slot 249/250
Probably won't resolve your issue, but still work fixing
Drag and drop your syscheck.csv onto modmii.exe and it will tell you what to do