Hyperveloce, no dimensions. One of the objects to my eye looks like a piece of large, hard-sided luggage.
The position of these particular targets is just at the left edge of the search grid done by BR-6 on June 6. While the report does not say, I assume it was this plane flying this grid that was involved in the initial sightings. The search grids are given in more detail than the previous BEA reports, and this sector (with the targets) was not overflown until June 6. (If I have erred in this, I'm sure mm43, who is far more knowledgeable, will correct me on that.)
These targets 18, 19, 20, are on the left edge of a grid scanned by Orion (sonar) and Remus (photography on the last day of the search, and a month after Orion). To the left and north of these targets is a void that was not scanned (or scanned with any confidence), or photographed.
If I recall the debris field for AI 182 correctly, smaller items first, with items getting larger and more numerous as one proceeded along the track.