Hello-I have a 1915 home in Maryland  where at some point the kitchen was moved to an area that used to be a porch. It has a brick raised foundation with two wooden panel access points and a dirt floor. The kitchen floor is freezing in the winter months and we need to insulate but there is so much competing information about doing this and not causing rot. I will be putting a plastic barrier down over the dirt floor before this work. So my question is—

1. can I use foil faced close cell rigid insulation between the rafters (Facing the foil up toward the floor) 
2. is it better to use reflectix? Certainly seems easier to work with and transport and staple this between the rafters with an area for trapped air between it and the sub floor?

3. should I then put foil faced rigid foam over the rafters and tape it for added insulation and moisture which also provides a nice clean look and hopefully discourages mice from entering like they do every winter

or is there a combination of these that is most recommended?
Thanks in advance!