Should I communicate to a researcher that I'll apply for a postdoc position is his lab in approximately two years?
Sure, why not?  Telling him you are planning to apply is not the same as applying.  He is not going to make an evaluation right now, so the drawbacks you mention don't apply.  You might also ask him what he regards as good preparation for working in his group.

The only part of this that looks bad to me is that you are planning in advance to do a second post-doc, rather than even try for a permanent position.  But I understand that may be the norm in some fields.