Hello Piotr,

Unknown said:

* Does SDL Cloud Machine Translation work both ways between English and Polish? (just MT, I am aware that Adaptive MT is not available for this pair yet)

Easiest way to find out is to try it.  It's exactly the same languages as are available with the free plan, you are just paying for more capacity.  Alternatively look here:

http://www.sdl.com/solution/language/translation-productivity/machine-translation/language-pairs.html

Unknown said:

* The basic plan includes a ‘dictionary’. How do I upload it, in what format, and will I be able to replace the dictionary when I switch translation direction (for example Polish into English)?

It's a TBX format... the Glossary Converter will make light work of this for you, but you can also export from MultiTerm if you prefer.  The dictionary is the same whether you go EN->PL or the other way around:

https://languagecloudsdl.uservoice.com/knowledgebase/articles/752397-how-to-create-a-dictionary-in-language-cloud

Regards

Paul