What advice do you have for navigating multiple stakeholders with conflicting feedback when creating sales enablement?

A few things come to mind to try:

1. Create a brief for the sales enablement assets upfront. Succinctly outline what your objectives are in priority order, who the target audience is, and some brief details on what’s important and likely to appeal to them.
2. This brief is also a great place to outline your RACI/DACI/RAPID to create clarity on what each person’s role is in the project.
3. When conflicting opinions arise, try to leverage your brief to realign the stakeholders around what is important. Bring them back to the target audience, what they care about, and the goals of the sales enablement piece. Hopefully, the brief can help guide the decision making. Also, if the feedback is coming from folks that have different roles in the RAPID, that can also create clarity on whose opinion holds the most sway.
4. Finally, get everyone together in the same meeting. Outline that the primary objective is to make a final decision on XYZ, so that you can get the sales enablement asset out into the wild, helping your company serve more customers with your amazing product. Make sure the decision maker is in the room to close out the disagreement with finality if it comes to that.

Good luck! Those dynamics can be challenging.

Politically, it's probably smart to go with the advice of the most senior person offering advice, especially if they are in your direct reporting structure.

As another option, supposing that one person told you they prefer "A" and another told you they prefer "B", show the two options to a few of your good reps and let them break the tie. I demonstrate that I've done the right things for enablement by showing that our reps actually use them.

I think it is important to have a strategy/vision with goals laid out for sales enablement, that is approved by stakeholders ( typically VP demand generation/CMO and VP Sales / Chief Revenue Officer).
Once that is good to go is when I would recommend creating a tactical plan which should be your ideas that are aligned with the above vision.   

I understand this is easier said than done, however, you need the backing of your manager who is prepared to stand up for you in case you face hurdles in going through the above process. 

Yes everyone in the organization thinks they can do marketing and I feel its the role of the marketing leader to let rest of the company know that his/her team knows what they are doing, are open to suggestions/feedback in their decision making, however, the final decision lies within the marketing function. 

The first thing to do is figure out the "why" of the conflicting opinions. Perhpas it has to do with the incentives each stakeholder is responding to, or a resistance to behavior change of some kind. Either way, this can potentially help reconcile those differences and produce something that everyone feels equally invested in. 

Marketing is the only job in a company that everybody thinks they can do. You’ll propose an idea and get conflicting feedback from everyone.

How I handle the situation is saying something like, “I’ve considered everybody’s feedback, tried to incorporate as much of your feedback as possible, and on the conflicting feedback made a judgement on the best path forward.”

You can’t please everyone. But most people just want to be heard and recognized.

How is your sales team set up? Do you have a sales training counterpart? Or is the head of sales?

Ultimately, you’ll need to set up a mtg with that person + your head of marketing and you to review proposals and to ask them who’s input is crucial. You will never make everyone happy - you have to become the expert and make recommendations and make sure you are aligned with the head of mktg and sales vision.