you dont need to put a coat over wood veneers nor have I heard of people doing so because they usually have a protective coat already when supplied - but each to his own right? soo...

1. when ever you use any oil coating the colour will change - no getting around it.
2. Ace hardware store and ikea has some of these oils like boiled linseed/teak oil for sale.
3. Tung oil sold by some craft shop in Klang Valley area but super difficult to use - takes about 3 months to properly dry - also expensive. www.multifilla.com ; shop.craftiviti.com