PS. The trouble with using 'Hi' as the spelling is it is pronounced as 'Hai' in English because it is a common word. It is better to change the spelling to 'Hee' to avoid laughter and embarassment to your kid when he grow up.
The first one (according to Campbell's Dictionary of the Amoy Vernacular) is ui (in Penang Hokkien sounds the same as 位 (place) but the tone in Amoy and Taiwan is slightly different. The second chiap (literary) or chiat (when it means "fast").
May be too late, but just in case... 易 = Ì or Yi, Yee, Yih, Ee etc 芸 = Ûn or Oon, Oen, Wen, Wun, Uen, Woon etc 恩 = Un or as above 宜 = Gî or Gee, Gie, Ghee, Ghi, Ghie etc 吟 = Gîm or Geem, Giem, Gheem, Ghim, Ghiem etc 妤 = Î•/Î/Û (depends on which Hokkien variant) ---> for Î•, some spelled as Er. 忆 = Ik or Yik, Eek, Yiek etc 萱 = Huan or Hoan, Hwan etc.