Hi, Georgios
Creating ceres::Jet from double scalar results into vector part (derivatives) being set to zero.
Thus, point projections will have zero entries in Jacobians, corresponding to derivatives by rotation parameterization.
If the only performance concern is speed of trigonometric operations, one possible solution is to use quaternions for rotation parameterization, since that makes group action on points expressible in multiplications and additions (with trigonometry being "moved" to Manifold::Plus or LocalParameterization::Plus, depending on ceres version, which are being called "almost" once per iteration for each corresponding parameter block).
Keep in mind that caching matrix of ceres::Jet might also result into problems, if vector parts of the Jets are inconsistent with function that is being auto-differentiated.