Conversely, I've seen datasheets with:
- ca. 10k dividers recommended,
- no specification for leakage current of FB pin,
- no discussion of how to choose those resistors (the 10k range is simply assumed as "good enough")
Had to contact TI via E2E forum to get an answer; turns out it was ~nA, as you expect for CMOS inputs. With the usual fluff about "we don't measure it because it takes too long", of course they didn't have anything to say about "why not at least 'max 1uA' or such?"
Probably the DS/AN author of the part I was looking at, should've swapped roles with the one you're looking at!

Generally, you can expect CMOS chips to use CMOS input structures (i.e., ESD diodes and gates), having very little leakage (say, 10 or 100nA for a bad part on a hot day); likewise, bipolar has to supply base current, so tends to pull up (or down) with some ~uA. But when you
need to know -- better off measuring it, get a sample or dev board and check. Second best, asking the manufacturer...
Tim