Well, inches per gallon is a very rough guideline, but it is usually a safe starting point. Adding up adult sizes:
molly: 3"
3x platy: 6"
3x angel: 15"
bristlenose: 4"
2x clown plec: 8"
7x corys: 14"
(rest I'm counting a little small - they're all light bioload fish)
5x white cloud: 5"
6x neon: 6"
8xH&TL tetras: 8"
You're at 69", very roughly. Generally, the rule is 1" per gallon, with 1.5" usually attainable in a mature tank (roughly 6 months after cycle finishes), and higher with good maintenance, careful compatibility considerations, and strong filtration. There's all sorts of problems with the system, it's a guideline, and a very rough one at that, you can't trust just the numbers. Also, there's a good chance many of these fish, particularly the plecs and angels, aren't full grown yet, which could make a difference of 5-15 inches.
They may not look packed now, but as the angelfish grow that may change.
I wouldn't add right now, but if your water stats are kept perfect and stable, there should be some room for future expansion, though not too much. The inch-per-gallon rule is a reasonable starting point, but ultimately, there's more art than science to stocking, as there's just too many factors to consider.
The main considerations here are twofold:
A. The angelfish may eat the white clouds, neons, and possibly H&TL tetras when they reach full size. Sometimes, if they grow up around the smaller fish, they won't see them as food, but the tetras and minnows have a shorter lifespan, and once the angelfish are adults, you probably won't be able to establish new schools of those fish (I've heard of angelfish raised with a school of 10 neons, but when 5 more are added, they pick out only the new ones and eat them). Probably not an immediate issue, and not a long-term deal breaker, I think, just something to keep in mind a few years down the road when the small fish are getting old. Also a preemptive head's up just in case you wake up one morning and only have 4 neons.
B. A more immeidate issue, with 3 angelfish, if two form a pair, the third will get the tar beaten out of him. Adding more might disperse this, somebody like Tolak would be better able to help you here, but you might also end up getting more pairs and even more fighting. If you add them, I'd only add 1, and if things ever get out of hand, be prepared to move the problem pair to their own tank.
I don't know much about clown plecs, but I know bristlenose sometimes hassle other small plecs. Keep an eye on them, particularly around food. if you feed something like zucchini, use two pieces in different spots so the bristlenose can't claim both. My BN will often claim and defend food he has no intention of eating, so it's important he can't claim everything.
