Indonesia is a sovereign country. Ur suggestion require the Indonesian government to give Singapore the green light, before SAF can land troops in Indonesia. Without permission from Indo government, landing troops there would tantamount to an invasion (regardless of the intention) and there is a possibility that Indonesia may declare war on Singapore on that basis. Thus far, I believe Indonesia has been rejecting offer of help from Singapore.
Ur plan will fuck Singapore so hard as i strongly believe that our fuck up SAF is no match for the TNI. So what if we've got all the fancy military gadget? These gadgets can only be as useful as the soldiers behind operating them, alas the bulk of the SAF soldiers neither have the heart nor the will to defend this piece of foreign loving shit island nation. I've seen how nationalistic the Indonesians can be, and this can somehow indicate to us how garang their soldiers can be as well. The TNI has seen actual combat while our gay SAF has zero actual combat experience.
I think economic sanctions from ASEAN, or threats of exclusion from ASEAN would be a better option, but it requires joint effort from the other ASEAN nations. Singapore alone is just too weak to economically hurt Indonesia into compliance, and in fact we need them more than they need us.
But then again, who gives a shit about Singapore? it is nothing but a meaty cow that is extremely easy to slaughter.