Hi Steve and welcome to the forum,
You will find contact details for the suppliers on all the supplier profiles in the directory. Just make contact with them by the contact method listed and you can then ask whatever you like.
In regards to the second part of your question, I assume you mean what if a supplier is selling in the same market place as you are at a cheaper price. Well that's a serious hurdle to over come and to be honest if a supplier is going to do that to you, then you need to ask yourself why you would want to even consider doing business with them to start with.
Yes, suppliers will usually have their phone number and or email address listed on their profile page in the directory. So you can contact them with that info or you can visit their website directly and contact them through their website contact page.
The LAB results are not linked to the suppliers in the directory, that doesn't mean that you can't find suppliers that carry the items, but you may not be able to. The LAB provides data direct from eBay, it is to indicate current eBay market trends in the US marketplace. If you do find something that you can't find in the directory, then you can email Link hidden: Login to view
with your requirements and the support staff will do their best to find you some supplier leads to follow up with.