I think you're seeking the best of both worlds and it's complicating your decision making.
You're willing to commit to 2 years 'IF' etc, and there's no way of knowing if you'll be in SG for 2 years. As it is your options are severely constrained by this, and this required flexibility would make it more expensive.
If such flexibility is that important then maybe your primary option is a Serviced Apartment
? Don't know. The flipside perhaps is finding a place on a TA with a break-clause after 6 months. But then you'd have to accept you might get terminated at that point too; would you be ok with that? Notice clauses cut each way pretty much evenly.
Do you honestly imagine relo'ing to SG then seeking to leave after 6 months? If so I don't envy the unpredictability of that. Do you feel able to commit to 12 months? Then you could see if you could agree a 12 month TA with it rolling automatically into 'month to month' afterwards, if that is what both parties agree. That would IME be a much more common arrangement, and so far simpler to find.
ps. I don't think you could activate a Dip Clause 'just because you wish to move on from SG'. Why would a landlord agree to such a one sided proposition?...