The old answer is that the trace identity you give in 2) is not quite right, Let $R=\sum_i a_i\otimes b_i$ be the $R$ matrix for $U_q(sl_2)$ and let $t$ be the $4$th root of $q$, then
$$t tr(XY)+ t^{-1}tr(S(X)Y)=\sum_itr(a_iX)tr(b_iY),$$
where $S$ is the antipode.
you can find it in a paper of Bullock, Frohman and Bartoszynska in Communications in Mathematical Physics in the late 90's where we proved that the space of observables for lattice gauge field theory based on a fat graph is the Kauffman bracket skein algebra of the surface which is a regular neighborhood of your graph.
To get the signs to work like you want you need to work with $-tr$. The minus sign has been explained nicely by Bonahon and Wong. It comes from the fact that you are looking at $PSL_2(\mathbb{C})$ representations and lifting them to to $SL_{2}(\mathbb{C})$ representations.
In more modern terms, quantum Teichm"{u}ller theory as developed by Fock, Checkov, Bonahon and Kashaev constructs a dual lattice gauge field theory, whose representation theory has been worked out by Bonahon and his collaborators. What is nice about this is you can emulate steps of the proof of the geometrization conjecture in the quantum setting and find fixed representations. Bonahon and Wong recently proved that the space of observables contains a large subalgebra which is the Kauffman bracket skein algebra of the underlying surface.
The quantum hyperbolic invariants of Baseilhac and Bennedetti end up assigning quantum invariants to knots and links in manifolds with a $PSL_2(\mathbb{C})$ representation. When the underlying representation is trivial these are the invariants of Kashaev which is have been equated with evaluations of the colored Jones polynomial by Murakami and Murakami.