The citizenship or nationality of the claimant doesn't really matter in a human rights case (that's why the ECHR is called the European Court of Human Rights and not the European Court of Citizen Rights or even the European Court of Justice). The issue is whether a human right - in these kinds of cases, the abuse of the right to property and/or right to fair tribunal - has been abused or not. Since the ECHR convention is a convention between state parties it is states which are typically the respondents. Because of this , in principle, TCs - irrespective of whether they are regarded as citizens of Turkey or citizens of RoC or even citizens of an unrecognised TRNC - may pursue cases against the RoC whether or not they live in RoC. However like any other complainant they must first have exhausted local remedies which means before a case could even possibly be lodged at the ECHR. In other words a TC would have had to have had their property heard by RoC courts and then show that either the procedure or the decision of the RoC courts or the subsequent action of the RoC authorities had still failed in some noteable way.
Jerry is right to say that ECHR is open to TC action, with the above proviso.
The question of pre/post 1974 has little impact in these cases. The issue is whether the effective local administration of justice has failed or been otherwise inadequate in upholding the human rights of a claimant. So, for example, properties seized or expropriated prior to 1974 could still be a subject of an ECHR case. Indeed, if I recall correctly a GC citizen of RoC won a case against the RoC for expropriation without compensation of her property (I think that a petrol station or road was built on her land).
Boomerang as usual derives a perverse interpratation from the ECHR cases. No the TCs are not milking the Turkish state. No it is not a strategy of TCs to double their gains - how could TCs have strategised in this way if the division of Cyprus occurred before the creation of the current ECHR ? And no using ECHR is hardly the path to rapid riches. Of course the usual class basis of 'justice' is revealed in these cases - you need money in the first place to secure redress. You won't find any impoverished or landless people taking cases to law, even if they have suffered a great deal more than those with title claims.