Do you really think any could actually be overdosed?? I'm a bit confused by what you seem to think has happened. It seems you are under the impression (having some experience in a similar area relating to mixing liquids) that even though I certainly lost some amount of sugar, the way fluid dynamics work is that some of the early bottles actually took in more sugar than they ought to have?
I really have no idea. Here are the three things that I do know and can assert with some experience:
1) Buckets drain in complex ways. It is not safe to assume that the stuff on the bottom was the stuff that drained out first, though it certainly could have.
2) If your priming sugar didn't get mixed well, there is a reasonable chance that it was unevenly distributed amongst your bottles. Maybe some of it drained out, maybe it didn't. Maybe the first bottles got too much sugar, maybe the last bottles did, and maybe they all got just the right amount. There's really know way to know through speculation.
3) Beer bottles start exploding once you get much north of 3 or 3.5 volumes. It doesn't take much excess sugar to get there.
I certainly don't mean to tell you what to do, but given the unknowns there is some risk here. The problem is not that the liquid spilled but rather that you don't trust that the priming sugar was evenly mixed. That is probably the most common cause of exploding bottles.
(As a side note, adding more yeast won't lead to overcarbing. Carbonation rates aren't effected by yeast quantities under most circumstances.)