Contrarian that I am, I don't feel anyone has done you a favor in their advice.
IMO, you don't need a specific recommendation of a single product to own. You need a recommendation for a system which will develop your confidence in selecting the most appropriate camera for your immediate needs and use.
Here is what I see as pertinent information you have so far given us,
"I mostly shoot landscapes and product photos, but occasionally go for wildlife and car shows."
One could reasonably say each type of photography you wish to pursue would require a discrete lens. Certainly, if we were still using analog gear, that would be the case for most photographers.
One advantage to digital photography though is the fact the shot is never finished until it has been processed and printed. This fact makes the case, though most "seasoned" photographers would probably disagree, for considering a single, fixed lens camera system and performing everything you need to do within your computer's software.
With your processing software you can stitch together extremely "wide angle" panoramas and "zoom" in close for cropped images seemingly taken with a long focal length lens. This can save you hundreds of dollars and multiple pounds of weight and confusion in lens selection.
Accomplishing such diversity would mean you could quite easily use an "enthusiast-oriented" bridge camera, possibly of the superzoom variety, if you truly feel your needs are so wide ranging as to otherwise require several high quality lenses to accomplish all you want to do.
You have no established a budget to actually work with. Your range as you have stated possible camera bodies suggests you've not really given this much thought or that you have money to burn.
No doubt, the Nikon D3300 would be an excellent choice in a package with two of Nikon's kit lenses;
http://www.amazon.com/Canon-Rebel-Digital-Body-Only/dp/B00T3ERM4Q
The Canon T6s takes a considerable jump in cost with little IMO improvement in image quality;
http://www.amazon.com/dp/B00X0BRLT4/ref=twister_B00T6P7QYS?_encoding=UTF8&psc=1
Actually, the T6s really has little to offer over the baseline Canon when it comes to image quality;
Recommended Cameras
DPReview Gear of the Year: Canon Rebel SL1 / EOS 100D
Unless you simply enjoy being the person who doesn't buy what others own, I tend to suggest you stick with the tried and true brands. They are tried and true for a reason and, for someone just beginning to use a digital camera, they have two distinct advantages IMO.
1) Their menus are the best thought out and easiest to navigate for the average user.
2) Their wide selection of available lenses which will mate with their consumer bodies makes these cameras an odds on favorite for having what you want
and what you actually need at the best price and best availability.
In addition to those distinct advantages both lines offer serious image quality at (subjectively) dirt cheap prices that is easily as good as most non-professional photographers will ever require.
All that said though, you could use a fixed lens enthusiast's camera such as a Sony RX100 IV or its Canon counterpart which would save you several hundred dollars (over the cost of Sony's latest camera) which you could put towards useful accessories.
For the most part, the type of photography you've mentioned is almost always accomplished in a "bright available light" setting. This means you do not "need" an extremely fast lens nor do you "need" a larger sensor.
"SX50 beats all my DSLRs"
A lowly superzoom, bridge camera will do virtually everything you could ask of a camera as of today;
Canon PowerShot SX50 HS Refurbished | Canon Online Store
(The SX50 is a discontinued model and its refurbished price varies with availability. Not that long ago it was available from Canon direct sales [with a warranty} for as little as $149.)
No doubt, all of the above has likely made you more confused. Which is why you need a system of selection which narrows down what is the most comfortable choice for you today. "Comfortable" is not synonymous with "best". "Best" is purely subjective and you have not determined or, at least you have not indicated to us, what you feel it is subjectively that makes a good camera.
It really is true that any modern DSLR or enthusiast level digital camera available today will provide the user with photos at the quality level they are capable of producing. There are few "bad" cameras out there today. You could almost walk into a store and pick a camera by pointing and you would have a camera that would provide very high quality photos.
The only impediment being your ability to extract them from any given camera.
This means you need to audition cameras by handling cameras. Do not get hung up on reviews. The job of a review is to point out the good points of a product and their static, studio set up tests are not a true indication of what you can accomplish with a camera.
The SL1 is as good as any other consumer Canon when it comes to image quality. It is smaller than the Nikon D3300 which will fit in larger hands more comfortably. The Sony is a bit of a game changer and will (literally) challenge many enthusiasts. The SL1 when fitted with a 24mm pancake lens is barely that much more cumbersome than is the RX100 yet it offers diversity in lens selection and a very nifty and useful touch screen LCD menu system.
You can see the logic is circular and you can drive yourself crazy going 'round in circles.
If you have a local camera shop, spend time there. Ask if they rent cameras for a weekend. But handle and, as much as possible, use the cameras as you feel you would in ownership.
Then go home and establish your realistic budget and a basic list of priorities.
What do you feel you need.
What do you feel you would like to have.
What do you not need at all.
How many cameras are left?
If you intend to do "serious" photography, I would say you need RAW capture and a hot shoe for a flash. Manual focus is desirable but not needed with today's autofocus systems. Beyond that, you matter more than does the camera.
Do your side by sides at home;
Side-by-side camera comparison: Digital Photography Review
Quantitative Pros and Cons: Weigh up Decisions With a Simple Approach
Narrow down your choices and head back to the shop to buy the camera that will be most compatible with you today. You cannot go wrong with any of your choices.