My suggested "fine tuning" and comments in bold:

The 24th is a Sunday, it will be relatively traffic-quiet in central Jakarta city so stay there. You can rest or hit some sightseeing highlights like Old Town, Museum, Square, etc. in a full day. Leave earlier on Monday, it will get you to Singapore by lunch and you'd pick up a more useable 1/2 day in Singapore vs an aggravating one in Jakarta. Change your departure to BKK for evening of the 27th, that's the better part of 2.5 days in SIN which is fine for an intro. I suggest skipping AirAsia for schedule reliability reasons and using SG or TG, might as well get some more miles, even if you need to fly economy. This gives you more useable time in BKK, and your hotel night for the 27th spent in BKK vs SIN will be cheaper for same class of accomm.