It doesn't matter if it is short term or long term investment as long as you gain profits on your investment. And also include Ethereum (if it is not included) on your 5 altcoins that you're going to invest in. There's no need for long explanations but it will surely rise again at the near future as there are many projects that are using its platform.
What are you talking about? Do you even know how trading works buddy? Short term and Long term investing are different and you need to decide which is better for you based on your personal preferences.
Most people prefer short term trading in order to earn quick profits, but I personally don't prefer this and instead prefer long term trading since I can stay patient for a long period of time.