If my memory is serving me right the 5th gen C61A Lancer Dolphin with 3 speed A/T has only been paired with the 4G15 73PS engine in 88-89, early 4G13 never came with A/T.
In 1990, when they launched the 12V 4G13 79PS, then it was paired with A/T.
Do not go for the old 4G13 1.3L engine with that transmission, strictly if you will install CNG.
If you will use it as point A to Point B car, and you do not mind slow acceleration, there is no problem.
The 12V 4G13 will work fine, even on CNG.