Well Lisham, The first one 'might' be H. nummalarioids but can't really tell from your pictures... if so, it has nice small white flowers usually with a red center and blooms heavily all at once (lots of pendicles at one time).
Second one looks like what we call "lipstick plant", not a hoya but related I think.
I believe you are correct on the H. lacunosa. Not many others with that alligator skin type leaf. Nice small very fragrant flowers.
Next one could be anything! I have a couple that look similiar but think you will have to wait for it to flower to ID correctly.
Here's a link to 'Stemma", a great little periodical that comes out a few times a year.
http://www.stemmajournal.com
They just started putting it online. Well worth the download! Their other links on the homepage (in black banner along the top) are also very good. The Thai hoya site, while mostly in Thai script, is still worth a look as most are named in Latin and I saw a lot of great photos with IDs there.
Good luck!