Since Latvia is a member of the Schengen Agreement, the rules of entry common to participating countries are .All of them are stated in the instruction "Instructions on the competence in issuing a visa by individual states of the Schengen agreement" .In this document, two rules are clearly spelled out: the first entry rule and the rule of the main host country .According to these norms, the journey you are planning is possible without problems, if these countries are used for transit and Latvia is the main host country .Otherwise, it is recommended to indicate in the visa application form the country of expected entry .