My first piece of advice is that you are perhaps worrying about things too much. If you like the kilt, then wear it, and do not worry about what others think!

As for how to accessorize the kilt, I think you found your answers in the pictures above. Note that in all cases, they are wearing a sporran, and in most cases a kilt pin and long hose. To my eye, this goes a long way to saying 'kilt', and not 'skirt'.

As for a jacket, a non-matching gray tweed crail, braemar or argyle (which you can make yourself, see the DIY forum) is a fine option. If you want something a little more casual, then a waist coat works, tartan is quite alright as you see in the pictures. If it is cold out, you could wear both. If it is warm enough out, and you want something even more casual, then just a shirt or sweater is fine too.