If you define hold for long-term, Ripple and LTC are not an excellent choice for you at this time. It is more appropriate to invest in ETH or BTC than investment in altcoins if the investment is determined and held long term. The exchange rate of the current market is unstable and if you want to be safe then only invest in BTC and ETH only.
You are right, Bitcoin and Ethereum are the best choices for long term investing. But we have to diversify and not go all in. Litecoin is excellent for diversification and is still good coin that promise good returns. I would suggest to stay away of Ripple.