By the original finish, I should have them done in BMF, but the space is too tight for my modeling knife, and probably I'm gonna end up picking them with a silver felt pen
Use a fresh No.11 blade. You'll be able to get into the spots near the windows with no difficulty. Also, when using BMF, having a mechanical pencil with 0.5 mm lead around is handy. The pencil lead is small enough to fit into any small crevices, allowing you to burnish the foil so it conforms to all of the details. When foiling side trim, scribing around the perimeter of the trim to create a recess will allow you to, in effect, tuck the foil into the recess and give the foiled trim a more realistic appearance.Personally like the stainless steel PE scribers from HQT Tools.
You can use the mechanical pencil to burnish the foil around the outer edges. The eraser on the mechanical pencil can be used to press the foil into scripts, badges and such without damaging these details.
As far as spraying clear over Alclad, you'll only end up with a dull, non-reflective silver paint finish. Read HERE for a detailed explanation.
For rechroming bumpers, grilles and wheels, forget about Molotow. The best product available to reproduce a mirror-like chrome finish is Alsa Corp.'s Easy Chrome. Unlike Molotow, which is an ink, or Metalizer finishes, Easy Chrome is durable and won't rub off. It can be clearcoated and used on 1:1 car/truck rims. It can be brushed on; but, the best way to apply it is with an airbrush, in light mist coats. You can spray a clear coat over it, which is not necessary; yet, the clear will not flatten the particles and dull the finish. The price for the 2 oz. kit might seem high; however, a little goes a long way. You can rechrome anywhere from 100-150 bumpers/grilles and wheels. Considering how much it would cost to have that number of items rechromed by a replater, it's very cost-effective. You can read more about it's use on models HERE.
BTW, this is not a "new tool" kit. It's a straight reissue of the 1999-vintage AMT/ERTL Chrysler 300C with updated box art.