If you need a CDP account to trade and hold SGx’s stocks in SG Market. then what do you call an accounted created with POEMS2.0, do I still hold the stocks at the end of the day after buying it?

Cheapest one is 'CC prepaid' (and on longterm view the fees are continously shrinking),

very good thing

You have to check carefully, some of the companies will store your shares in custodian account while some will store it in cdp account. there are difference between both of them, it depends on your preferences. if it is in cdp, it is under your name, but if it is in custodian, it is under the name of the instituition.