The GRN battlecruiser is slightly weaker than the LABC, but hardly enough to compensate for the Valor's OP-ness. The GRN and LN gunboats are fairly equal as I've been told, but I'm no expert on gunboats. The GRN lack a cruiser, while the LSC can hardly compete with the Obstinate (you'd have the equal number of cruiser-class ships in the fleet, and mixing LSCs with LABCs would only weaken the LN).
The status with the BAF is only slightly better. The Dunkirk is a fishy copy of the LN dread, but the Crecy, one of the best destroyers around, alleviates the balance gap a bit. It can somewhat compete with the Obstinate if it manages to keep distance, but the Obstinate will manage to tank it in many cases simply due to the ship class difference. The official BAF| can use up to 4 LABCs however, as far as I remember, which can be good weapons against Obstinates. The Crecy can deliver a considerable punch to the Valor, but the Valor will usually be the winner, not only because of the FG, but also because it takes just one mistake for the Crecy to lose. The BAF GB will eat the GRN GB alive in a duel, but it will be one of the first ships to fall in a fleet battle due to its relatively huge size.