Q:

Question regarding Steps with multiple approvers within an Approval Process?

Is it possible to allow users to manually choose two different approvers for a Step ? Or is it possible to have one of the approvers automatically chosen and the other manually chosen ? 
From what I see, a Step which allows for manually chosen approvers only allows one manually chosen approver. And the only way to have multiple approvers for a Step is to have them both automatically assigned.

A:

Is it possible to allow users to manually choose two different approvers for a Step?

No. You can only choose one approver if you Let the submitter choose the approver manually

Or is it possible to have one of the approvers automatically chosen and the other manually chosen?

No. You can only choose either Manual or Automatically Assigned but not both

From what I see, a Step which allows for manually chosen approvers only allows one manually chosen approver. And the only way to have multiple approvers for a Step is to have them both automatically assigned.

That's correct. This is how the approval process can be setup.
From documentation:

When multiple approvers are selected:
Available only when Automatically assign to approver(s) is selected.

