Awobodia wrote:is it possible for my wife to switch in-country to being my dependant?
No. If you want your wife to change to dependent of Tier 1 (General) migrant, she will need to apply from home country. This said, you may want to defer the decision until such time that both mother and child are able enough to travel.
As for the child, you may wish to apply for leave to remain as dependent of Tier 1 (General) migrant from within the UK before your wife (and child) travel to home country OR you may apply for leave to enter (EC) for the child from the home country when your wife and child reach there. The choice is yours - but the child will need a visa to return to the UK if he/she travels abroad.
regards