What do you mean by "allround plane?" Do you look for a model that is piston-,turboprop- and jetfan-driven at the same time, suited to transport 1 or 300 people 50-5000 miles for the same operational costs and is abundant and cheap on used market ? Sorry, but without any idea about your company goals and fleet politics you canīt expect any answer that would really help you.
There is an important rule for newcomer airlines you already start to break : keep your fleet lean ! Every new type adds costs for maintenance not additionally, but exponentially.
You already ordered two types that generally serve the same task: small short routes. If you plan to also serve other markets you need yet another plane. I would apply for a mentor who can better lead you through your first steps.