I'm searching for a small(ish) and relative light telephoto of at least 200mm, mainly for still photography, that is black and inconspicuous to the layman's eye while traveling in "adventurous" offbeat areas in eastern Europe, Africa and South America, and photographing musicians and performers during concerts/festivals.
Seems an easy choice based on what you shoot, really. The 200mm f/2.8 is the winner. It'll allow you to combo with a TC to shoot wildlife and be good for general tele stuff as well. And you can use your 40mm and 100mm to fill the gaps that are left by not having the 55-250.
I've owned both lenses, and I must say I do miss the 200mm. I sold it because I needed the general purpose zoom, but, I'd own both if I had a reason to. Which, is a consideration, btw. Not sure what the used market in your area is like, but here in the US, the non-STM version is like $100ish, and the STM is $150-175. Would be worth owning in combo with the SL1 (and eventually maybe a 17-55 f/2.
as a lightweight walkaround combo.
But in the short term, definitely get the 200mm. You can zoom with your feet if needed.