^^sis Ella, this is what i suggest:
March 2 10AM (Sat) arrival:
- check in sa YMCA around 11am, have lunch and go shopping na at Orchard para maibalik ninyo yung pinag-shopping ninyo sa YMCA before moving forward w/ your day. kasi nasa same area na ang Gardens by the Bay - No Signboard - MBS eh. say 11:30am to 3pm kayo sa Orchard.
- so after dropping your shopping bags at YMCA, proceed to the Gardens by the Bay (say 3-5pm), then MBS (say 5:30-7:00), then dinner at No Signboard kasi nasa area near MBS na to (say 7-9pm), tapos balik na lang kayo sa MBS waterfront for the Wonder Full Show at 9:30pm.
(sis, when you say MBS, what exactly do you want to do there ba? hehe. yung Skypark? kasi kung Skypark, best to go up there yung late afternoon pa-sunset, para you have views of both daytime and nighttime. that is, if you really want to go up there, kasi kami di na kami umakyat kasi view lang naman meron dun, hehe. so if you decide to forgo the MBS Skypark, you can extend your time either at Orchard or at the Gardens, tapos after the Gardens derecho na sa No Signboard for dinner, then MBS waterfront for the Wonder Full Show)
Mar 3 - Johor Bahru because it seems that you really won't let this go, hehe (Outlet, Legoland, Hello Kitty), dinner sa Makansutra (Esplanade) or Lau Pa Sat
Mar 4 - travel and early check in sa RWS (either Hard Rock or Festive Hotel), USS and Sentosa
Mar 5 - check out then head to Changi outlet, 5pm departure going back to Manila
- you mentioned Chinatown for pasalubong... normally tanghali pa nagbubukas ang mga stalls dito, so maisisingit mo lang to sa Mar 2 or Mar 5, kasi whole day ang Mar 3 and 4 mo. pero masyado nang haggard ang Mar 2 mo eh... unless after check-out na lang sa Mar 5, segue muna saglit sa Chinatown before going to Changi outlet...