Is it permissible to link future destiny with present actions, while believing that everything is by the will of Allah?

There is no harm in expressing future expectations conditioned upon certain causes, while believing that everything is by the will of Allah. The expression should be speculative, not definitive, for only Allah knows the unseen. And reporting about the future should be conditioned upon Allah's will. Allah Almighty has linked causes to their effects by divine decree, and the causes themselves are part of the divine decree. Only Allah knows what would have been if something that did not exist were to exist.