\- Skilled Hamon users know that silver horseshoes are the best conductor- Lucky is not one of those ponies
\- Centaurs aren’t directly weak to sunlight, in this version of events the Hamon techniques used against them are just harmful in general and are able to counter their magic
\- The Red Stone of Aja is a known artifact in Equestria (as a powerful conduit for magic), the centaurs wanted to seize it and use it together with the power of the rising sun (celestian magic again) and become ultra-powerful, taking over Equestria overnight, but their shenanigans didn’t go unnoticed and they ended up being defeated by the Pillars (Starswirl’s gang) ironically enough
\- Santana, Eisidisi and Wamuu end up being sent to Tartarus. Still alive technically, just extremely weakened
\- About Kars’ defeat: back when Luna was banished, the magic from the Elements and Celestia combined was so strong that it left small traces of that spell, which was conducted trough the RSoA. also something something last hamon something something friendship is magic