27 amps controller will quickly kill that size battery.
But not if you use self control, and run slow. Then you only pull 15 amps, which that battery can handle better.
Keep it below 20 mph, with less than full throttle on starts, and you can use that battery. Really, to ride fast with that kit, you should have 30 ah. 20 would do, but it would not perform real good. With a 20 ah pack, voltage will sag a lot under load, and cause lower capacity on the ride, and lower top speed. But a 20 ah will at least last a few years.
If you are stuck financially, get the 10 ah now, and if your kit allows speed limiting use it. Then get a 20 later, and by running the two in parallel, you will then have a great 30 ah battery, that you can ride long, or ride hard, as you want.
The bms should not be a big problem, but if it is, its because you gave it full throttle on the take off, which will kill the battery.