Playing ...e6 should be totally fine to counter these setups from White. I saw you claim in the comments that this would lose tempi for Black compared to the main lines of the Leningrad Dutch. This is not true, since White never plays:
- Bc4 in the mainline Dutch;
- c3 in the mainline Dutch.
So White has made at least one completely useless move in direct conflict with the ideas of the mainline systems for White in these cases. What does this mean in the long run? It basically means that you have more freedom in carrying out your plans, since the plans you mentioned only serve one purpose which is terminated by the move ...e6.
Tempi will most likely have to be wasted trying to rectify White's mistakes in the opening (because c3 seems terrible and will probably have to be corrected by playing c3-c4 at some point anyway, and Bc4 is an easy target for the black pawns now that it isn't safely placed on g2 staring down Black's queenside).
You don't have to be worried about potential tempi for a standard plan in the MAINLINES when White is playing a total SIDELINE IN DIRECT CONFLICT WITH THE IDEAS OF THE MAINLINES which will enable you to play according to different ideas.
In general, when your opponent does something strange/non-standard in the opening you should try to think of the possible drawbacks of the deviation played, and when you study the opening you should try to figure out why the mainline is played the way it is by both sides.