Initiating the process of project development is a pivotal moment for any business or enterprise looking to evolve or innovate. This crucial juncture is where the selection of the right team member can act as the fulcrum for the success or failure of your project. In specific, the Scala programmer, a linchpin of modern software development, is a role demanding a thorough examination. But how do you separate the chaff from the wheat? How do you discern a competent Scala developer from the pack that aligns with your project and company ethos? The answer lies in the questions.

A deep dive into the abyss of Scala programming is tantamount to taking a journey through the labyrinth of computer science. At the core of this labyrinth is the choice of a suitable language for programming. Scala, which is an acronym for “Scalable Language”, is a statically typed programming language designed to express common programming patterns in a concise, elegant, and type-safe way. It smoothly integrates features of both object-oriented and functional languages, thus making it a first choice for many programmers.

Before you initiate the interview process, it's crucial to differentiate between the experience levels of developers: novice, intermediate, and expert. Three aspects to consider are the language proficiency, problem-solving capabilities, and knowledge of the Scala ecosystem. It's a complex triage that needs a detailed interrogation.

Starting the assessment, it's advisable to comprehend the candidate's understanding of the basic Scala principles. Questions could revolve around the object-functional nature of Scala, the ability to explain the Static versus Dynamic typing debate, or the distinction between immutable and mutable data. A comprehensive understanding of these principles is fundamental for building robust and efficient software.

Beyond grasping the fundamentals, an intermediate Scala developer should possess a firm understanding of functional programming paradigms. This includes concepts like higher-order functions, currying, immutability, and persistence. Probing questions encompassing these paradigms will help us gauge the developer's ability to write clean, efficient, and scalable code.

Taking it up a notch, an expert Scala developer must demonstrate proficiency in Scala's advanced features. Delving into the concepts of type classes, implicits, futures, and the collections library can be a litmus test for their expertise. Furthermore, their familiarity with libraries and frameworks like Akka, Play, and Slick, is also a significant indicator of their ability to work on complex Scala projects.

However, the assessment of a potential Scala developer doesn't just end with technical prowess. It's equally important to understand their problem-solving skills. Questions that present real-world situations or problems can serve to highlight their ability to apply their technical knowledge creatively and effectively.

An overlooked yet critical aspect is the developer’s knowledge of the Scala ecosystem. Are they aware of the latest developments and best practices in Scala programming? Do they follow key influencers and contribute to open-source Scala projects? An affirmative answer denotes a developer who is not just using Scala, but contributing to its growth and evolution.

Nonetheless, the journey doesn't end here. The developer’s synergy with your project and your team is the ultimate criterion. This requires understanding their approach to teamwork, their communication style, and their flexibility in adapting to ever-evolving project requirements.

Ultimately, the quest to find the right Scala developer for your project is a multi-faceted undertaking that requires a deep understanding of the Scala landscape. Remember, the effectiveness of your questions will directly reflect on the quality of your candidates. Shaping them smartly will ensure that you bring on board a Scala developer who is not just technically proficient but also aligns with your project and company ethos.