Supposing

1) Suppsing/suppose you have cleaned the room tomorrow we will go shopoing

Jest ok czy mysi być "by tomorrow" tak jak z if?

2) let't say/suppose you have cleaned the room tomorrow. What do you want to do next?

Tutaj już ok. Nie trzeba "by tomorrow" prawda?

Czy tylko z if, unless i if only musi być by tomorrow a reszta on condiction provided i tak dalej może być tomorrow?

1 by
2 zupelnie zle, zly czas

Let's say you will have cleaned by tomorrow- tak?

Let's suppose - mogę z suppose użyć future perfect?

(Let’s say, let’s suppose) you will have cleaned the room by tomorrow / in time for the party / in January next year / before Sue arrives /… All those time adverbials are possible.