"Break" a measure to add repeat marks

I'd need more context to say for sure - the full PDF would be useful - but it looks like a typo to me. That's a double-sharp sign, and I can't imagine why it would be called for here. I think they probably meant a coda sign.

Sorry, no idea. Hopefully someone who has seen this type of marking will come along. I can tell you that it is not standard. Even if you were to reproduce it, MuseScore and most musicians would not understand it. We might need the full PDF you are working with to figure it out.

Yeah, looks like they are trying to create an extra-comple roadmap with two different codes, but they didn't know how to find a second symbol, so they faked it using a double-shapr symbol. Definitely not recommended, unless this is a common style in your region (it isn't in most of the world). Instead, you should use the coda variation provided already in the palette to get the proper playback possibility, and then i would recomment edit its text by double-clicking it, and clarifying it as either "(+) 2" - where (+) is the regular coda sign - or two sign signs. You can access the coda sign from the Special Characters palette (press F2 while editing text to display).. Or, if you decide to use the double-sharp sign after all, you can add it from the same palette.