Hi Prasad,
1. To get the header and footer visible to be visible when exported to excel you can use the below workaround.
a. Hide the existing header and footer
b. Create two blank cells and use them as header and footer and also select the setting repeat for every page so it will be similar to header and footer. these will be visble when exported to excel and will serve as header and footer.
c. To make it look neat and clean you can try relative positions. 0cm from top of report for header and 0 from bottom of last block for footer so that when exported to excel it will be intact.
2. This is a bug and also if you notice the font style will also be converted to default irrespective of the font that is used in the report.