ATTiny would definitely work. Ive use them for really really long timer systems with some trial and error.
You should maybe just look at a bigger battery depending on what lifetime you would expect? They are not exactly super low power(at least the ones I have used)
Limpopo is definitely more backward. But Free State does have that small town redneck vibe going for it in many places. Also dont talk shit about my Brakpan. It gets that reputation because Springs people holiday there