The crop factor for the 1DX2 shooting 4k video is just a little more than the crop factor you get with the older Canon 1D APS-H bodies.
To get the equivalent of 100mm you need a lens around the 70mm mark; 60mm will actually frame more like an 85mm equivalent.
There aren't any first-party primes between 60-75mm. The closest you can get in first-party prime lenses would be either a 50mm or 85mm, and use extension tubes for closer focusing. To get that focal length with Canon lenses you have to use a zoom; there are loads which hit that 70mm ballpark.
There are some third-party lenses in that focal range which could be adapted. None are made with the EF mount, as far as I'm aware.
Quite frankly, the 1DX2 for 4k is a bit bizarre. You can get better 4K quality and a wider selection of focal lengths with smaller systems, like Sony's α-series, Fuji's X-T2, and the Panasonic GH5. The Sonys and the GH5 include in-camera stabilisation so you can more easily get smooth video no matter what lens you use; all three have a wide range of lenses available and, due to being smaller mounts (and not a large mount with a digital crop, like the 1DX2) you can adapt nearly anything to work with them. More importantly, they're simply far better for video; the image quality is better and the file sizes are more controlled.
If you're shooting a lot of action stills in harsh environments, and then doing occasional 4k video on the side, then sticking with the 1DX2 makes sense; I'd advise the 24-70 f/4 IS, with its semi-macro mode, as the most sensible option for getting video with the framing you're asking for. Second to that I'd say pair your existing 100mm with a 50mm (with extension tubes for close focusing; the 50mm macro isn't that great to be worth bothering with) for a basic long + normal duo. The 50mm will result in a field of view roughly the same as 70mm in 35mm framing terms, which is long enough to give a flat perspective but is wide enough to frame up to a full-length person quite comfortably, in most spaces. Again, the zoom would really be better.
If you're not shooting winter sports, standing in the middle of a desert dust storm, chasing wildlife halfway up a mountain, or if video is your primary medium, then, quite frankly, just scrap the 1DX2. For the cost of filing out a range of lenses to do video with a 1DX2 with the framing you want, you could get a better-optimised video system.
Lastly, there is one secret weapon which might suit you. The old Canon FD range includes a handful of 55mm f/1.2 variations. FD lenses can't be mounted to EF without losing infinity focus and increasing their macro focus, but since you're asking for macro anyway, that might be fine for you. Since you're shooting video, the lack of autofocus shouldn't be a problem and, as it has its own aperture ring, you can have it de-clicked for video. Add a small extension tube to get true macro. All of the FD 55mm f/1.2s are very soft wide open, of course, but stop them down to f/2.8 and they're good across the field, and that goes doubly so for cropped-in video. If you won't be using it for longer distances (no infinity focus) and you really want the closest thing possible to 60mm (to get a bit-over-80mm equivalent view), those FD 55mms are the nearest thing you can get.
But, again, I must stress that doing something like adapting an old FD lens to a 1DX2 to shoot 4k video, when systems like the GH5 and X-T2 already exist out there doing this natively, is really insanely pointless.
That's undoubtedly the correct understanding.
