Firstly the asteroid belt is between Mars and Jupiter, not Jupiter and Saturn, so does not correspond to the abyss.
You are quite right: asteroids do not correspond to the abyss. The asteroid belt is surely the remains of an organ contingent on human balance (lost via the Fall), for it lies between the airy (gas giants) and watery (inner planets) layers of the solar system, air being more active than passive, water more passive than active.
Secondly, as Fianic notes there is no reason not to have Mercury on the left and Venus on the right of your diagram to make the Golden-Dawn-style attributions work.
Yes, Venus (pulchritude) is on the male side, being what drives lust in the male; Mercury (power) is on the female side, being what drives lust in the female. For the male-female pairs on the triadic Tree represent, in descending order, the chaste male-and-female, reproducing male-and-female, and lusting male-and-female aspects of the psyche.
Thirdly, if you're exploring planetary attributions with the Sephiroth, what about the older attribution with Saturn at Geburah and no planet in the three Supernals? It messes with Chaldean order, but otherwise has much to recommend it--Jupiter/Chesed, Saturn/Geburah, Sun/Tiphareth, Mars/Netzach, Venus/Hod, Mercury/Yesod, Moon/Malkuth.
Much misdirection has been afoot even—nay especially—from the earliest days of Qabbalah proper (12th century) and even far earlier, when Ma'aseh Merkavah (the Work of the Chariot) was the Jewish esoteric tradition (since lost, along with the keys to Qabbalah itself, thus necessitating my painstaking reconstruction of their main outline). As it happens, planetary attributions to Sefirot can be deduced with certainty from number itself. The elementary layers occur in natural order (fire-air-water-earth, or from fine to gross), each contained by the square of its element's number: fire (total energy conserved, the stars) is 1; air (turbulence, the gas giants) is 2-4; water (form, cohesion, inner planets and moon) is 5-9; and earth (earth's crust) is 10 (the solid being what one holds in one's ten fingers). This explains also their functions: 2 (sun) receives fire's (1's) energy, while Saturn and Jupiter, then, act on water (3) and earth (4), water being more active than passive; 5 and 6 (numerically minus-4 and minus-3, respectively) are water's ability to act on earth (4) and on itself (3), while 7-9—being minus-3 through minus-1 in VALENCE—are the aspects of the watery layer that are acted on BY water (3), air (2), and fire (1). As indicated by its sophistication, the system of thought embodied in Qabbalah is a relic of the last civilization (destroyed at the end of the last 'ice age'), not of the primitive times between its fall and our rise.
Fourthly, similarly, if you're looking at the lightning flash, is there a path from Binah to Chesed (and Geburah to Chokmah)?
No, there is not, at least in the paths of the 'Tree of Return', which is the other thing I can show behond reasonable doubt the Hermetic Kabbalah gets right. That is WHY it is called the abyss: the lightning flash crosses it but leaves no 'trail' to follow back up, evidently. The Tree of Descent may be different in this respect, but its paths are for nature's use, not ours, I dare say.