2.a) Newton's First Law, or Law of Inertia

According to Wikipedia, Newton's First Law states that in the absence of external forces, all bodies remain in their state of rest or linear uniform movement unless a force acts upon in.

Newton's First Law, or Law of Inertia, introduces or establishes many concepts at once, which I suppose form part of the context of the set of Newton's Laws. Among them, we can point out space, time, movement, and force, keeping in mind the spatial geometry, that is, motion and the direction of forces.

Globus normis 

Newton includes the concepts of Euclidian space and absolute time in the initial or axiomatic fixation of concepts in his dynamics model; which fully coincide with the Theory of Global Equivalence. It is not the only coincidence since the new theory upholds the argument of Newton's Laws as far as being a completely mechanistic theory, and it does not acknowledge any magical effects from other dimensions or other worlds on physics reality.

However, it seems that the context of the dynamics model of Newton's Laws is situated in a completely empty space where not even gravitational forces, fictitious forces or forces that appear in non-inertial systems exist. In spite of the level of such radical abstraction, in many ways Newton's First Law almost accurately establishes the inertial characteristic of the movement of bodies through the reticular structure of gravity, or globine.

The main problem with Newton's First Law, or Law of Inertia, from the point of view of the Theory of Global Equivalence becomes evident through the motion or variation of the spatial position of globine and its effect on the movement of electromagnetic energy and the energy of the bodies.

The response from Quantum Mechanics in face of this problem is to assign probabilities to the spatial position of the particles given it is incapable of calculating the spatial variation of the reticular structure of gravity since this does not exist in the model.

Obviously, Newton's First Law, or Law of Inertia, as well as the rest of Newton's Laws of dynamics suffer from their limited applicability to other types of movement. You can try to adapt the concepts to the new reticular context but I don't think it is always the most adequate and sometimes it is better to create new concepts and terms, in order to avoid that the same word have too many meanings that always have to be accompanied by the corresponding clarifications.

Another disadvantage of Newton's First Law, or Law of Inertia, is the concept of the definition of force since the forces of gravity or fictitious forces do not always behave like what we would call normal forces, just to be clear on this.  We will see this problem later when we discuss Newton's Second Law.

Einstein's Theory of Relativity attempts to resolve the two previous problems by making it so the speed of light is artificially constant. Therefore, the variations due to the movement of globine and the effect of the tension of the longitudinal curvature of globine, which make up the radial symmetry of gravity, on light and mass are resolved mathematically by playing down time and space.

The fact is that Einstein's Theory of Relativity creates more problems than it solves since, besides the countless singularities and the lack of basic Physics concepts, it denies the real existence and effects of the reticular structure of gravity, thereby seriously hindering the advance of science during an entire century.