White hose have 2 advantages:
1 In general they are cheaper (I bought half a dozen that worked out at no more than £2 each)

2 They can be dyed any colour you want. I am currently learning about natural plant dyes. I am looking to make a chocolate brown colour.
Ghillie shirts (especially if they are white or cream) can look a bit 'folksy', a bit 'dressing up as a Scotsman'. Again, it's cotton, why not dye it? You are wearing the Black Watch, so a nice bottle green would match nicely.

A lot of kilt wearing is 'make do and mend' and 'adapt and modify'. It won't be long before you are looking at a jacket and find yourself saying "If I change the buttons..."

Personally, I would loose the backsword - that is a bit too 'Braveheart' and will cheapen your look. Sell it and invest the money is a really good sporran or an expensive sgian dubh.

You have made a good start - keep going!

Regards

Chas