Hi,
There are a number of good tripods to choose among.
In general, get the best you can justify. Not only will it last a lifetime, possibly serving several different camera systems equally well, it will also be more enjoyable to use and less likely to get left in the hotel room or car trunk.
As others have said, you do have to consider the rig's maximum weight capability. Not just the tripod, but the head and anything else that's involved in supporting your camera equipment. Try to allow for any future system growth, but generally speaking the more weight a tripod can support, the heavier it is itself. So, you'll need to strike a bit of a compromise.
I'd recommend carbon fiber. It is not only lighter, it also dampens vibrations that might "ring" through metal. And, it's a little more pleasant to handle in cold weather. It does cost more, though.
The fewer sections a tripod leg has, the more stable the tripod will be. Of course, more sections allow it to collapse into a smaller package. These two factors are at odds with each other, so this is another trade-off to consider.
A center column can make for less stability, too. Particularly if it needs to be extended a lot. If the legs extend tall enough to work comfortably without any column, that's about the steadiest design. However, it's makes for a less compact tripod and some columns can be reversed to allow very low angle work. Still more trade-offs to think about!
Yes, there are different type of leg locks. On several occasions I've caught my sleeve or pant cuff on the lever type and had a "near-death" experience, so I prefer the twist type.
Will you be using quick releases? If so, there are several types. The most common and universal is probably Arca-Swiss. Many other companies make compatible lens and body plates and other accessories to fit A-S, and it's been around for a long time now. Just watch out for unique, proprietary QR designs, for which accessories might not be available in a few years.
Personally, I'm using two tripods: one for studio, the other in the field.
My studio 'pod is an ancient, aluminum Bogen (now Manfrotto), big, heavy, but rock solid even after 25+ years use. It's on a dolly and casters for ease of use. It's got a gear driven center column that has extra bracing and is pretty stable. It also has a leveler under the head, with a bubble level. I can't believe I actually carried this tripod down into the Mesa Verde cliff dwellings... once... when I was younger.
In the field I use a Gitzo 1325 CF with a Kirk BH-1 ballhead. This 'pod has a three section leg, no center column, and a quick leveler with a sight bubble. The legs can be spread quite wide, to allow very low angle work even without a center column. For large telephotos, in particular, I use a Wimberley Sidekick gimbal head on this rig. By the way, a Sidekick also works very well to quickly orient a camera (with a short lens) vertically, eliminating any need for an L-bracket.
I also use two Bogen/Manfrotto monopods, each fitted with Bogen/Manfrotto ballheads.
I use Arca-Swiss QR plates on all my cameras and lenses. The Kirk and Wimberley both were designed to fit A-S. But all the Bogen/Manfrotto heads had to be modified to accept A-S.
Shop carefully and maybe you'll never need to buy another tripod!
Cheers!
Alan