here is a short side-note before I answer your questions: the NTG4+ is a shotgun mic, it might not be the best choice for indoor use (it has an interference tube: it works great outdoor for making the mic more directional, but not so much indoor because the sound bounces off the wall). But if you were to get only one mic for your use-cases for budget reason, I think the NTG4+ is a good choice: it is a solid performer, and though there are better options for podcasting it will still be much better than the webcam's integrated mic.
Regarding the use of a shockmount for podcasting:
The Rode RM5 clip is most likely good enough for that usage. A more elaborate shockmount is required for booming, as it greatly reduces handling noise and other unwanted vibrations. If the mic is mounted on a static stand indoor there is little need for a shockmount, unless you walk really heavily on a creaky wood floor.
Regarding the popfilter:
For the use cases you described you don't need one, the foam sleeve shipped with the mic is good enough. When I use a mic indoor I only use a foam sleeve. If you plan to shoot outdoor though, you'll need some fur (like a deadcat) to attenuate the sound of the wind. And if you plan on shooting on very windy sets, you will need a blimp (if it is too expensive to buy, try to rent one).
Popfilters are usually required when the mic is very close to the mouth and not placed at the ultimate best spot. Some say that they alter too much of the sound, but installing a popfilter is easier than finding the best mic placement and for podcasting (not "sudio singing"), the sound alteration is not important.
Regarding the stand:
Any kind of heavy/robust stand would do. For example: the Rode PSA-1 would work fine, as it is designed to support much heavier microphones. But I would recommend to use a more traditional stand such as the K&M 25400: it is easier to manipulate and much cheaper. If you plan on typing on a keyboard while podcasting, don't put the stand on the same surface as the keyboard (or use a shockmount)
Mic placement is important. For capturing the sound of a person talking in front of a camera, try to set the mic just out of the field of view of the camera, a bit higher than the head of the speaker, and aim at the mouth. In most situations, it allows to capture the speech while minimizing other sound sources (such as a car passing behind the speaker). It is nonetheless wise to experiment on your own to find the best placement for your room and your use-case.