What strategy is the best for small investors ? Moving the money into altcoins or just pulling completely back ? Should we expect a soar on altcoins (e.g litecoin, ripple, antshares a.k.a neo) ?
Pretty easy. Pull all of your coins into a wallet you control (like bitcoin-core, running on your own computer), and then just ride through the storm. For some amount of time, there may be 2 or 3 versions of Bitcoin that are active, but if you use this strategy you'll own all of your coins on all the versions.
So, as long as the combined value of every version is approximately around the value of the original version, you haven't lost any money.
Then, wait for the dust to settle, sell the coins for the versions you don't like, buy coins for the versions you do like, and then resume using Bitcoin like you had originally.
The altcoin market is pretty upside down right now, even more than Bitcoin is. It's probably less safe to move to an alt than it is to just ride through the bitcoin storm.
If you are the only one with access to the secret key, then you control the coins. If someone else has the secret key (or keys), then they control the coins.
I believe copay is okay from a brief glance, but I honestly can't tell if they give the keys to Bitpay for backup or not.
The safest wallet is bitcoin-core, though there are plenty of reasonably safe options.
I used bitcoin-core before, but I wanted to switch to a more light-weight wallet, and one which is based on BIP32. At that time copay looked like the best option. And because it's BIP32, I should be able to transfer the wallet to another compatible implementation without any problems.
The million dollar question. If you look back at what the Ethereum split did for the market, maybe it'll give you some ideas.
Remember though- if you don't have any Bitcoin under your own control (non-custodial wallet) you might not be able to trade between chains if there's a split. There are only two exchanges with announced pairs AFAIK- BitFinex and ViaBTC both have futures contracts set up.
