What color door will make my new green color pop work with the brick?

I agree - lower R front corner will give you a wall on the R that you can arrange "foyer" type furniture on (hall tree, breakfront, narrow table with mirror above). Furniture can group around fireplace more easily then, and the area on the R side of the living room becomes a traffic area leading into the house, to the stairs & back of the house. That's the way the traffic wants to flow anyway - don't break up the living space by having the door centered and traffic flowing right into the center of the room. By moving the door to the R, you'll also have a bigger front porch area at the left end for chairs etc. Widen the front porch gable so that the front steps are centered on the new front door location. Another idea is to delete the R side of the porch that wraps the corner - it looks as if it isn't covered and seems like an odd & awkward space to me.

The style of the front door and the closet doors are inconsistent with MCM. They may have been replaced at some point. The original doors were probably flat - no panels. The new front door you've chosen isn't MCM. The floor is probably original as it is identical to the one in the '60's house I grew up in. I'm not sure which direction you want to go in. How have you decorated the rest of the house? You have an opportunity to change the doors and return it to its MCM roots. Since MCM is all the rage now that doesn't conflict with "modernizing" it, but you said you want to bring it out of the '60's. If you want to go in the direction of transitional style you shouldn't do a horizontal railing and you should change the flooring.

I think that a wooden deck is in keeping with your home’s style (which is fabulous, by the way!). You could explore using Ipe or a synthetic decking material in a dark tone. I don’t think that you will be able to match the stone on your home, so I wouldn’t even try. You might also explore better, more interesting modern lighting for your entrance way to make it more inviting. Do you require house numbers anywhere on your facade? In the end, I am sure, you will explore a renewal of your landscaping. But I would keep the porch in the forefront as you work on siding. Your house will be beautiful when you are done!