Hi Cikgu Sew,
1. For Selamat Jalan, am I right to say that it is used when a person is leaving for a longer period of time? E.g. Travelling overseas etc.
That’s right. It’s a greeting to wish for a safe journey.
However for Selamat tinggal and Jumpa Lagi, can it be used interchangeablely?
Yes. Typical of see you and good bye being used freely in the daily exchange.
2. For a situation such as driving through the immigration checkpoint and leaving the customs officer after getting the passports chopped, would terima kasih be a sufficient response?
Terima kasih is sufficient as it is a transaction of stamping your travel document and checking your boot. No jumpa lagi as it is not the nature of the encounter unless you really like to see the officer again elsewhere.
3. Also for greeting wise, may I ask whether there is an appropriate term for the English word “Hi/Hello” in Malay?
Hello is roughly Selamat sejahtera. Apa khabar may also be a quick equivalent.
Hello was a signal call for hunting in the jungle and the word was considered rude when hello was suggested as the opening greeting in the beginning when the telephone was invented by A. Bell. However people forgot about its origins and moved on with hello.
Nowadays you have different types of greeting…try calling the 1800 of Banks
It’s “welcome to ….”
I know some used moshi moshi as the signature greeting
Another person used meoooow as the signature greeting
So hello may be privatised!