They are certainly all problem coins.
The 1834/3 Do RM 8R is in my opinion most likely a genuine coin. If it was counterfeit, or if I suspect it most likely was I would be bidding.
The 1726 Mexican Ecu is possibly a counterfeit. But I am not 100% certain.
The other two I would have zero interest in.
The price is already far too high.
My book on Counterfeit Portrait 8Rs is available from Amazon http://ccfgo.com/TheUnrealReales
or from me directly if you want it signed.