Wah ur son so gifted ah. My gal 7 mths still boh gay, dunno how to crawl, dunno how to pull herself to standing position yet.
For the mash potatoe, steam the baby potatoe/buy those potatoe that is used for making mash potatoe (remember to ask, coz not all potatoes can be used to make that). Then smash the hot skinless potatoe with a bit of butter. Butter will melt when the potatoe is hot, so it will be easier to blend.
As for the papaya porridge, use green papaya, and dun worry abt the taste coz I got a shock at 1st when my mum cooked it, but after tasting it, the porridge is actually very sweet and the cooked papaya will turn orange and soft. Thus u can mash it and feed it together with the porridge.