Let’s start with the most obvious: all instances of a HDTV are wrong. Since the abbreviation is unpronounceable (hence, it is not an acronym), it is read out in full, as ‘aitch-dee-tee-vee’. Because the string begins in a vowel, we need the indefinite article an rather than a: hence, an HDTV. Similarly, we ought to say an HDB flat, not *a HDB flat.
The writer’s use of a suggests that, like most Singaporeans, he pronounces H as ‘haitch’. (This pronunciation is Irish, and is often attributed to the Irish nuns teaching in Singapore schools in colonial times.)
Things are a bit different, however, if an abbreviation is not intended to be read out the way it is written. To illustrate: StdE feature and SgE feature are intended to be read out as ‘Standard English feature’ and ‘Singapore English feature’, not ‘ess-tee-dee-ee/ess-gee-ee feature’. Therefore, a StdE/SgE feature is preferred, not an StdE/SgE feature.
The other errors in the article concern modals. The Standard English versions are given in brackets: You’d also need (You’ll also need); you don’t get (you wouldn’t/won’t get).