Hi Danlee, 

The answer to your question is a yes in my view. 

BABOK (which I should state right away, I am not a fan of) states the Planning aspect of BA work should always be undertaken at the very start. The reality is that this can rarely happen, but that's for another discussion. So common sense should come into favour instead. 

First of all you need to be able to plan who your stakeholders are going to be, what area of the project they will be the SME for. Make sure that you have a Stakeholder for each part of the project. 

Your approach to them is a part of planning in that you need to consider what they are the SME for and this is ALL you should be discussing with them (they will try to tell you more and have their opinion on other areas, but these opinions are not your primary focus as they are not the SME for that area). How you approach them is useful to know beforehand as there may be certain techniques that work better for different stakeholders. So planning this beforehand is important. 

Knowing when you can meet with them is also important to know beforehand. For example, if you don't meet Stakeholder 'a' on Friday, he is off for 2 weeks holiday. So you know you need to speak to him on Friday or earlier if possible.

However, often things change in a project, and sometimes your requirements may need clarification or require a new look at them (lets say because the project budget has been cut). In this instance, just start your planning again, and make changes as required.