Well, for me your actual configuration is much more adapted for Agile than for a 300+ developer store (not quite sure how Agile was implemented there, I would like to hear more about it, because scaling to this size requires a very high level of maturity on Agile IMO).
So, my answer would actually be the following: starting with 4 people, all values and methods are appropriate and valuable. In fact, what Agile methodology did you adopt earlier? What practice have you implemented? What makes you think that they are not suitable?
PS: , , Agile () ( Scrum). , , , .., , , . Agile. Agile - - . , Scrum, .