I don't think it requires the Asian countries to abandon or move away from any existing agreement. China is doing what all super powers do - create a near geography of reliant and dependent countries. US, UK, France and much of old Europe were doing that with grants, aids and soft loans for years. Though these are now managed more carefully due to movements within their country to stop exploitation.
China's previous approach of engaging the lower third of 3rd countries particularly the African countries have delivered mixed results with considerable backlash from the local population. Besides grabbing Zambia copper mines, the rest have held on.
They have realised that after the South China Sea issue, Asia is where they have to operate in. To date Pakistan and Sri Lanka have become completely beholden to China as a result of large loans which both countries cannot repay. In a matter of weeks and months, they will takeover an entire port which they built with loans provided by them. There is no traffic to the port and the Sri Lankans cannot repay and they will therefore take a majority stake. It will become an excellent and their first naval base outside of China making them a true blue water navy.
So now they have an excellent land route into Europe thru Pakistan and into the Mediterranean via Sri Lanka.
The question that has to be asked is why the Sri Lankans built a massive port that has no traffic while the current port is capable of handling traffic. And we all know why Najib dropped his pants and went to China. He too needed to replace the stolen funds from the treasury.
Does OBOR serve the dual objective of getting Asian nations to rally around china and abandon the TPP which is castrated to begin with now that the US has pulled out?
Clearly OBOR is a way of consolidating chinese power at a time when the US is turning inwards and moving to become an insular superpower. It is also a way of china to reduce its reliance on US controlled sea lines and in the long run make US geopolitical dominance of the Pacific less of a problem. Good for allies of China and extremely bad for allies of the US like Singapore