Tip: After editing your overworld, make sure to use an EMPTY save file, as save files with progress may load Mario's position based on previous versions of the overworld. Note that altered level flags will also only take effect on new save files.
And if you just want the castle intro from the original game before you enter your custom level, select in lunar magic, choose FG/BG GFX 1.
After that you need to select Level->Change Other Properties... in the toolbar and uncheck Disable "No Yoshi" Level Intro (if applicable).
Thanks! My entrance to a castle (but the level does not start at the castle) leading to an airship is working!
Just guessing based on a common issue, is it loading a weird room? The credits will load whatever level is specified as Yoshi's House (level 104 by default), so if you've edited that level, it will look different in the credits as well.
No, are all the sprites that are bugged (looking like they're bugged GFX, like the SMB3 hammer bros without SP4)
Well, if you have some knowledge about creating songs that can be inserted with addmusick, you can try to recreate the music with the smw instruments or try to somehow rip, if you are not very knowledgeable you can use midis and tinymm, but you need to fix some flaws, I recommend you read the tutorials on how to create a song that can be inserted with addmusick, if you know someone in smwcentral who knows how to create songs that can be inserted with addmusick, send a message if he can create or tear
I'm not aware of how to create songs that can be inserted with addmusick, but I've already seen some comments on this.