You can forget about finding indie games on SG/Asia PSN store. The number of indies there is laughably miserable. Even if an indie game is available, it only appears after months/years later (only exception is when a brand new indie game, not available in any region before, gets offered as PS Plus free game).
For PS4 version, just get from other regions (create a US/Canada/UK psn account, buy psn card digitally to top up wallet, buy game, play using SG psn account if you want).
For Vita, too bad, Vita is single account, if you buy using US account, you have to play using the same US account. If you want to play using SG psn account, have to get physical version but usually these indie games don't have physical version. (Some times a company called Limited Run Games do make some physical vita games, like Shantae 1/2 Genie Hero, but they are really limited, unless you camp and buy the minute pre-order goes up, no chance liao.)