No, each Travel Pass can only be used in the respective country. For example, a Singapore Travel Pass can only be used in Singapore, while a Malaysia Travel Pass can only be used in Malaysia.
Yes, you can purchase the Travel Pass in your home country. The travel pass will be activated upon date of purchase and expire in 4 weeks from date of purchase.
Travel Passes are exclusively for international travellers, and cannot be used within your home country. You can however purchase and use Travel Passes in other Southeast Asian countries.