What is the best way to get these two on one page for marching folio sheet?
Yes. I did that and it worked for the score, but not for the parts for marching folio. It worked for parts in standard size paper(8.5 X 11)
Just to mention the obvious: Layout Options are per layout, so be sure to set this also for your Part Layouts
Could you show this in Engrave mode, or better: could you share the Dorico project file?
When I reset the layout all it did was move the top two staves down to the original place. I had moved them up to make room for the staves on page two. So, nothing really changed.
Making room for things by moving them manually doesn’t work in Dorico; manual adjustments are meant to be made at the end of the process, just to tweak things. The idea is to work with the settings (in this case, mostly Layout Options) that Dorico gives you to get the look you want.
At a glance, I suspect you can make your page margins smaller and also your flow heading top and bottom margins. You might also want to make your Layout Name, Title, and Flow Title paragraph styles smaller in the parts to give you a little more space (this is in Paragraph Styles).
As @TonH suggested, if you can upload your Dorico project file here, someone can offer more specific suggestions.
Can you upload the project?
By the way your page margins are very, very generous, on a marching folio you need any space you can get.