Renderotica

For more adult work you would probably need a conforming Genital prop. If I remember correctly with V4 era Daz never made a genital prop for the females, they attempted to get by using Genital crease morphs until Genesis was released and grafts were introduced.

Lali's Bits by Erogenesis is probably one of the best options for V4. It does most of the work via morphing the pubic area and then using a prop for the labia, saying all that does make it sound archaic, but it works and looks a lot better, than some of the conforming genitals for V4 out there. (Many of the conformers you would end up with minute gaps between figure and conformer, and most weren't mapped the same as V4 so you have to open texture you want to copy in Photoshop, open texture template for the gens, and then sample an area of the skin texture and paint it over to the texture template, and in the end hope you painted it in a way that doesn't leave a huge seam)

 

 

As to the outfit check to see if it has movement morphs in the skirt or handles for the skirt (I have the outfit in question but am in the middle of testing, so can't really look at it at the moment) a lot of the heavy lifting for skirts back with V4 were accomplished either via morphs in the skirt part of the outfit, or by adding bones and Handles to control the movement of the skirt. Usually if the handles are there they will be a cone or circle in the view port just a hair below where the skirt is.

 

 

Ditto HV3, I also have a fair bit of V4 content I still want to use and I do like the near but not quite real quality of V4 era mats for some works.

I use the Lali's Bits for V4, they are very good plus you get some useful boob morphs and a lovely Lali character to play with.
Installation is not exactly push button and you need to follow the instructions carefully but worthwhile. I'm not sure if you can apply them to existing characters, I never got that to work but I created a 'base' V4 figure with the bits installed and the Lali character dial at zero. Now I simply apply the other character's shapes and mats to that. Properties Pre-sets can be used to transfer poses, adjustments and so on that you want to keep from existing characters.

As for the clothing: You are never going to get V4 clothing to fit like later generation stuff with higher poly counts, enhanced rigging, auto-fit and so on but there are ways to get good if not great results with the older stuff. First explore the scene tab to see if the item has bones that can be manipulated to suit the pose, check for morph / pose dials and as mentioned above look for handles, these may be off by default but if the item has them there will often be handles on / off pre-sets provided.

There are also many other tricks and technologies that can be very helpful. Deformers can be an easy way to fix little bits of poke through although simply adding a smoothing modifier may be even easier. Mesh Grabber is a great tool for in scene geometry manipulation from simple tweaks to complex shape changes. Also check out dForce, bit of a learning curve and does not work on some items but can achieve very authentic fits, drapes, etc on the figure, furniture or floor. There are loads of vids on You Tube showing what can be done with these tools and how to go about it.