Is there any way to make the NPCs / love interests NOT look like shadows during the animations??? Some setting or a mod?
Depends entirely on how you want them to be represented in the sex animations. Are you asking for the 'shadows' to be totally dynamic like your character, in that it reads the physical characteristics of each NPC involved, and then draw them (e.g. male/female, hair length, hair style, breast size (if applicable), eye colour, what they are wearing and state of undress, etc.)? Or are you simply asking for the good old anime-styled generic 'faceless (wo)men' thing? Because there are two main problems with this, the first being shared between generic NPCs and Love Interests (LI), and the second being from the LIs themselves.
The first problem is the classic problem: you need not only coding support to be present, but someone to actually do the drawings for each 'shadow' involved. I think at this time, the most 'shadows' you can see is maybe 3 (PC in doggy style while in a foursome with one NPC 'in front', one below and one above), or maybe 4 if it also accounts for someone 'behind' (the max number of penetrations for female PC is I think 6; double blowjob, double vaginal and double anal at the same time). Should they have the same level of 'detail' as the PC? Or should only LIs have it, while non-LIs all be drawn with generic shirt/pants/skirt but otherwise all look the same?
And then we have the second problem: what the LIs actually look like. Now, this is the most important part because Vrelnir himself have said multiple times that how the LIs actually look, other than the in-game descriptions provided, is otherwise deliberately left vague so that the player themselves can interpretate how they look themselves. Once you start drawing them in sex animations, even if simply drawing their outfit on a visible non-shadow body, it starts becoming 'officially, this is how (LI) is supposed to look like'. Using female Whitney in school uniform as an example - does she only wear the bare minimum required (top and bottom with School trait), or does she actually wear the School trait socks and shoes as well (and if so, does she wear the 'default' ones or the loose socks/mary janes)? Does she have her top untucked to her skirt, or does she actually have it tucked in? Which School top does she wear, and if it's one of the other ones than the School Blouse the PC starts with, does she have a few buttons unbuttoned, and/or have her sleeves rolled up and/or have the cardigan tied around her waist? A lot of these details can be shown in some way in the sex animations, so as mentioned, once you start, you start telling people how their husbando(s)/waifu(s) doesn't actually match what they thought they looked like.
On that note though in recent memory, there's only been two attempts at different sex animations 'artwork' - Mysterious (mostly centered around the PC, and feels like mostly made for females with flat-small breasts) and Hikari Female (also mostly centered around the PC). I actually liked the Hikari Female combat animation style but they broke with the 0.5.3.x update and Hikari themselves had disappared from the modding scene for some time by then. DoLP and the community is otherwise kind of maintaining what works from it similar to how BEEESSS was being propped up for months by community packs as well; otherwise someone would have to wrangle with Hikari Female combat animation coding to make it work again.