[recommendation for orthopedist in BKK?]

Aside from the great suggestions above, you can also check out Samitivej. 
 

[Dentist recommendations in BKK?]

Check out Thantakit Dental Center. Awesome work and wonderful experience overall. I was also offered a 10% discount for cash payment). 
 

[Airport and heavy coughing?]

Not an issue. If you're that worried, best to get a medical certificate before flying but I think that everything will be fine. Cheers.
 

[ferries]

Traveled to Lanta last year in late April. Was still able to get a ferry from Krabi to Lanta via  PhuketFerry. Best to confirm with them through their site if your dates could still be accommodated. They are pretty easy to contact. Cheers. 
 

[How to live for 4000 baht a month. Not inc rents.]

Wow, frugal indeed!

[Food truck, restaurant on wheels, restaurant on trailer, how would you do it ? Have you seen something different ?]

The idea is promising. Would love to see a foreign-looking mobile food truck but yes, make sure that it is geared towards the Thai market, but could still meet the foreigners' palates.
 

[Bangkok Bank Question]

Yes their system is pretty straighforward. Cheers.

[what do you bring from Thailand when visiting the West?]

Have always brought Thai spices, chili sauce, and the same old, same old fridge magnet. :'D

[How do you deal with the heat? Seriously...]

Take a bath twice a day, always wear deo and light clothes. Always walk under the shaded part of the streets. Use an umbrella or wear a cap/hat. Don't wear any hair gel! Always have a towel handy and drink lots of water! It's already the start of the early rainy season so the heat should be a bit bearable for now. Glad that I'm able to surpass the scorching heat of April and May in Bangkok. Whew!

[Men's clothing brands that will be cheaper at Thai shopping malls?]

Guess items are a tad cheaper compared to the ones in the US. I've noticed that US brand-name apparels aren't really cheaper in Thailand.