Maybe you should decide what you want before you start buying up all those axles.
Out of what you have and assuming the 50 and 60 are fronts.... I'd go with the 60/10.5 or 60/14b. Both the 10.5 and 14b axles are stronger than the 70. The 50 is an abomination. The 70 will be work to convert and not really sure how much aftermarket support is there? The 14b has much better aftermarket support than the 10.5, but everything is available for the 10.5. The 14b aftermarket used to be much less money, but that is/has changing.
To make the decision, look at bolt patterns and the wheels you have.... can you make one of those setups work? If not.... look at what you're going to have to spend to get the 10.5 or 14b setup for your scenario.