I don't know how well are you familliar with situation on Balkans (except for other fellow ex-Yugoslavian brothers

). Anyway.....
I have a question. will Kosovo be an independent country or what? would it be part of SCG?
I don't know how 'historically correct' or possible scenaro are you trying to build here.
researches i read about (sorry couldn't help myself

) shows the following:
if the war broke down in the Balkans (greatest possibility is of course Kosovo) the war would not spread (for now). but if the nationalists come to power in SCG (is happening now or will soon happen), Albanians in Kosovo demand independent state more actively (also happening), nationalists in Albania came to power (not happening) and most importantly NATO & EU forces leave Kosovo (will not happen soon).
that could ignite 'Bare Baruta' - and the war would be here. if that happens Serbs in Bosnia would most probably revolt and either join Serbia or declare an independent country (again).
Croatia is a big question mark. trying to deal with the past and join EU on one side and on the other are nationalists forces still strong. if these win (nationalist part of HDZ or HSP) it could join the war or most probably - carve up Bosnia with Serbia (it tried to do it before).
Macedonia (that is its constitutional name - FYROM go to history) will most probably not join the war with Albania on the side of Serbia. They will crush the albanian uprising - thats for sure. but war? they almost crush the uprising of 2001 - and that with (partial) help of bulgarian arms shipments (weapons meant for scrapheap

). i don't beleive it would join the war - unless the Albania openly interfere (arm shipment, military missions, soldiers,...) with their crushing of Albanians.