Remove 3 variables trying to access another scene's nodes

[CI09]

and added a replacement function. Also disconnected unnecessary signals.

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[hhyyrylainen]

This is starting to remove a good number of variables but I think there's still some more stuff that can be moved to the editor entry button scene to avoid needing to specify those in the HUDs.

[hhyyrylainen]

This is probably fine now, I assume your testing hasn't brought up any more problems with this.