Asian and Latin fonts

I have documents which are a mix of Asian  and Latin fonts  and I am having difficulty with footnotes and endnotes. Their numbersare in roman numbers and can be used in the midst of both the Asian and the Latin text passages.  The first difficulty I have encountered is if I want to change the Asian font style say by increasing the font size then when I try to do this the footnote/endnote numbers change font size as well 
For example I start with font size 18

then I change the font style on only the asian font part using a style which puts the asian font to size 10 , but the asian font does not change but the Latin font does

Clearly something is not set correctly - but what?

My second question is regarding the Font dialog - this is how I currently have it set. But I am not entirely sure what the boxes marked actually do 
and would much appreciate clarification and each and/ or good tutorial link for using mixed font registers in general.