Cool! Especially that the degree of outcrossing is heritable. That would be handy to work with!
Many herbs (including some common or widespread weeds) have tiny flowers on a scale similar to the lentil (as seen on google

) The creeping types of Speedwells are just as small. Some are early spring, others a bit later. Prunella vulgaris is a common weed/herb also low growing and small flowered which blooms in summer. These are the sort of plants that grow in your paths or any bit of bare ground that's commonly walked. Mother of thyme and other ornamental thymes that bloom profusely are very attractive to pollinators and can be walked over as well, or grow on the side of your path.
Most of the taller classic herbs have small flowers as well, including culinary herbs like basil

and perennials like thyme, hyssop, oregano, lemon balm, the mints, and others like mugwort, taller speedwells, vervains, betony, and so on. Except for thyme which is early summer, these are mostly late summer flowering. Oregano is very invasive so caution for that.
Bumblebees work the small flowered herbs (which get loaded with spikes of tiny blooms) as much as the smaller pollinators do - and also like the vetch that is a weed in my garden, but I wouldn't recommend you grow that on purpose near your lentils, as I believe they are susceptible to the same fungal diseases. Vetch is terrible for mildew whenever it's humid in summer, some clovers are as well although some are not. I find the red clover here is susceptible but I have a yellow clover that isn't. The clovers are also made up of many small florets no bigger than a lentil's.
I suppose you're in a dry climate?
I adore lentils and would certainly grow them if I thought they had a chance here, but I doubt it. If you find anything like resistance to fungal diseases, let me know.
