
1. As long as you respect the folder structure, everything should work fine. Otherwise, remember that, in Latex, the path is always relative to the .tex file, not .cls file. So, you should set the correct relative paths to font from CLS (../../Fonts/...). 

2. If you want to compile from multiple places, Give absolute paths to fonts. Something like, /Users/.../Fonts/..

3. When importing cls file in tex file, remember to either keep them in the same folder, and do \documentclass{leelavati}. Otherwise, give the right relative path to the CLS, like \documentclass{../leelavati} in the current structure.

4. We have done some Latex magic so that you do not have to keep writing \begin{english} \end{english}, or \begin{odia} \end{odia} to switch between English and Odia. However, as a result, using other fonts becomes an issue. Like, constructing the chessboard in the rooks-fighting.tex file. So, you would need to use \XeTeXinterchartokenstate=0 for those special cases. A small price to pay in our opinion :) 

5. \setstretch{} sets the line spacing, with the recommended values of 1.1 to 1.2 for english and 1.25 to 1.35 for Odia.