A couple of quick observations: Marsh Fritillary certainly isn’t endangered in Var. I have visited two sites in the past week and could have counted hundreds at each, and it occurs in most places. Nice photo of the “white” female Spotted Frit, Guy, but here’s one (14944) that would be hard to beat for blackness (and it has a deformed wings and antenna, just to add to the weirdness factor).

The female blue (#1) - I would go for Common rather than Escher’s, on the grounds of the uph marginal lunules look very much like Common, which is very variable down here although I have never seen the orange raying as on this one. On more circumstantial grounds, Escher’s is generally not common and the female seems quite rare to me – I guess I see 20 males to every female and I cannot recall seeing a female for a couple of years (and I do look at a lot of undersides). The female underside is very characteristic, so if you have an underside shot of this individual, I think it would be clear-cut. Perhaps more significantly, Lafranchis gives the flight period as from June (exceptionally end-May) and if it were seen before 14 May I would think it unlikely to be Escher’s, especially a female as they usually emerge a week later than males. This isn’t absolute by any means but the probabilities point strongly to Common.
Re Common/Chapman’s, I think there is a unf cell spot just visible above the hindwing? Always assuming I’m looking a the right photo. As Guy says, there are pointers and the unf cell spot is a good start (I have never seen Common of the form
icarinus, so cannot comment on this) but you need to be sure you can see enough of the unf – quite often the unf is tucked down and it just looks like there is no cell spot. The other pointers are: the male is quite a distinctive violet-blue, quite clear when you’ve seen a few; the unh marginal black spots sit nicely and centrally within the white area (in Common some/all are usually touching the orange); and Chapman’s is usually seen sitting on sainfoin.
In passing, Black-eyed Blue seems considerably more widespread in Provence than I have ever seen it before. I never thought of it as common (or, at least, frequently encountered) until now.