In reply to Currency symbols:
Thai newspapers moved from Thai to Arabic numerals in the early eighties, and publishers followed suit. These days Thai numerals are seen only commonly on currency.
I'd include the Baht, and the other ones, as they only take a minute or two to design. As a designer, the extra characters are a sign of a good quality font.
On a related note, the Numero sign (№) is quite useful to include too.