Is it permissible to sponsor an orphan for one year with the intention of renewing it later, by paying the amount to a charity and communicating with the orphan remotely, and will the doer of such an act attain the reward for sponsoring an orphan mentioned in the noble Prophetic Hadith?

You should do good deeds with the intention of doing so, and Allah does not let the reward of those who do good go to waste. Start by sponsoring an orphan; if your situation permits, continue, otherwise, Allah does not burden a soul beyond its capacity. It is permissible for you to appoint a trustworthy person to deliver the money to the orphan.