I had the same dilemma. I started a thread on Canyon bikes because I was deliberating like you. At the end of the day I went with a Canyon and I’m uber happy with the purchase process and the bike. My two closest riding buddies bought the same bike after me and they have been thrilled as well.
Here are my answers to your questions:
All out race XC or HT?
A HT is probably in this day and age the all out race option between the two. For people that are gram counting and want every weight advantage the HT is the “all out” best option for that. But, looking at the pros, Jonathan Lee (does Yeti even make a HT? I think not), and most (not all) of us on the forums here I think most people would send you down the full squish path more often than not. If you want to you can lock out the suspension and climb like mad on a full squish and it will be faster descending and more comfortable too.
So I would go for the XC race bike.
How do others choose a bike and how do you justify LBS or direct?
If you are doing a fire road climby course like Leadville then a case for a hard tail can be made. For most courses I don’t think the weight difference outweighs the suspension benefits of a full suspension bike. So that’s how I would start - full suspension. Then you can look at your options. Do you ride for a team? Associated with a bike shop? Ex military? Friend of a friend of a friend? If no to all of those then you are paying retail wherever you go so go wherever you want. Your budget is more than enough to get you a killer ride. As others have said, Scott is good value for the money and you have to decide what is most important to you. I don’t mind wrenching my own bike so for me buying online was not an issue.
I weighed the options and went with a Canyon Lux. This one is in your budget and gives you a great bike with 120mm travel up front and great specs on the rest of the loadout.
Other folks will have strong opinions of what they like as well. You will get a lot of good advice, good luck.