I believe a persistent chain split would be a disaster for Bitcoin and will almost certainly lead to one of the altcoins taking over Bitcoin's role. Probably Litecoin as it is the closest cousin to Bitcoin in spirit, which is why I have diversified part of my coins into LTC a while ago. I don't see Ethereum taking over, it's just too centralized and can't scale nearly as well as LTC can. Also Ether supply has no limit, which is a no-no.
I have the same opinion. I'm afraid that the date could affect everything in the bitcoin world. Buying some altcoin as an investment is a good thing, it can keep us awake if the bitcoin price has drastically decreased. Some altcoin does have a good prospect, I think litecoin, etherum, ripple and stellar have the same chance to be top altcoin.
Yes, there could be an opportunity for many of the Alts to take a place but I seriously think they still cant take over the bitcoin. The price of the Etherium, LTC and ripple may grow high but I dont expect them to counter the bitcoin and its price at all.
There are many people currently converting their bitcoin to fiat and to the Alts but still the ratio of converting bitcoin to fiat is high. In my opinion people will buy the bitcoin again but once the hard fork filth is over.