Please help with identification of these plants

I am currently doing a research project which requires that I survey a landfill and identify the plants, but I am having trouble with identification of some of the plants. Am urgently in need of identification help as I cannot identify some of my plants with the books supplied by my mentor and internet resources.
Can anybody please help me identify these plants?

Unidentified plant 1



Unidentified plant 2



Unidentified plant 3




For the one below, I'm referring to the plant with red flowers.
Unidentified plant 4








Unidentified plant 5




Thanks! :)

 

Where do you do your survey, in Malaysia? Or is that landfill at a different location?

 

My survey is done in Singapore's landfill, Pulau Semakau.

 

I tried to find something about your plants, but gave up and came across this website.
Maybe this will help you further:
http://www.greenculturesg.com/forum/

It is a forum just like this one, but it's called Green Culture Singapore.

 

Thank you :)