There are probably as many recipes for Basteeya/Bastilla/Pastilla/B'steya, etc. as there are names for it in English. I have made it several times (quite a while ago now) but I am a terrible person to ask for a recipe as I am sure that I probably just read about it and winged it in the end. I therefore would not be able to give you my recipe unfortunately.
There is one good thing about that though - it means you can use what you have and not worry too much about anything but the ultimate taste you want. I think you probably should have tasted what you consider a decent Bastilla at some time before attempting to make it or it could be quite a surprise if you follow a recipe that makes the end product way too sweet for your tastes/intentions. I have, as far as I recall, not actually ever put confectioner's sugar in the body of the 'pie' (only on top) but some recipes seem to lean that direction. Instead I think cinnamon. cloves, allspice, mace, etc. lend enough of a sweet inference. And I have never attempted to make Warqa so Phyllo/Filo/Fillo for me was always the fast answer.
However, if I were you I would find a chef you trust (David Lebovitz? Paula Wolfert?) and use one of their basic recipes, but if you don't have some ingredient on hand such as a particular prescribed spice (or spice mixture) then fake it with some others. For instance, Ras en Hanout - some recipes call for that spice mix and others avoid it entirely substituting instead just some of the spices that are predominant in that mixture. Lebovitz's recipe: http://www.davidlebovitz.com/2013/11/chicken-basteeya-bstilla-recipe. I don't have a link to Paula's but apparently it can be found in her Couscous book - maybe someone else can find it if you don't have that book either, gulfporter. I suspect hers is very authentic but may be a lot more work. David's looks fairly straight forward and familiar to me.
Here is a link to a site with pictures of the process - again the recipe is not 'kitchen tested' by me so I apologize: step by step bastila recipe with photos