7% is not all that much, normal is below 10%, so don't let that worry you to much yet. They expect birthweight to be regained by 2-3 weeks, so you have time to meet that target. Even after this if your baby is healthy then I wouldn't worry too much about it, these are averages and guidelines and some babies are just slow eaters. (Mine took 8 weeks). Remember that 2oz/60g is the difference between before/after a feed of full/empty bladder, on a small baby that's a lot of variation.
If you want to supplement or switch to formula then do so, if you don't then don't. It's your baby and you're doing the feeding so it has to work for you, but don't let anyone bully you either way. Stress doesn't help with milk production.
There are support groups who should be able to help, it doesn't mean that they will. But it's worth trying. And if one doesn't suit try another. If nothing else you might find someone else in the same boat.
Hind milk is sort of a thing. My understanding is that the fatty bits stick to the sides so doesn't come out until the free flowing milk has. The milk you produce is always the same (over a day). So if your feeding every few hours for about 10minutes then the consistency will be different before and after. If you have a grazer then it's more likely to be average milk all the way through because it's not hanging around.
Pumping increases supply in so much as the stimulation says you need to make more milk, if baby is suckling all day then that should do the same thing. It's also probably not a supply issue though. Most mothers have over supply in the first week or two. If you give baby expressed milk in a bottle the get a slow flow test as baby is unlikely to be used to a fast flow from you.
You don't need to express It you don't want to, and frankly It sounds impractical for you. It's advised because it's measurable as much as anything else, and those numbers don't often help if you're still feeding directly. If you're expressing after every feed to top up then you could just feed some more (assuming latch is good etc). It can be helpful in other ways though. If you find you have an excess in supply at certain times of day when baby isn't interested or its not convenient to give a long feed you can use that later. It can also help you identify when you have more milk so you can encourage better feeding then, or when baby might want more so you know she wants to stay on for longer then.
It could be Tounge tie or it could not. Get it checked. But until then babies can feed with minor tt, it's just a lot harder for you both, so just keep going.
Make sure your eating well. That means staying approximately the same weight and eating when hungry. If you're losing weight you probably should have more calories, if you're gaining weight then it's not going into the milk. Your body will sacrifice itself to make milk so listen to cravings.
If you're feeding every hour then you can't feed more often. So anyone telling you to either isn't listening or doesn't believe you, in either case talk to someone else. Equally don't feed to a schedule, I don't care how many paediatricians tell me to, you don't leave a hungry baby crying to teach them to drink quicker.
If you're feeding extensively try burping mid feed (every 15minutes or so), less air means more room for milk.
What seems to be working for us is learning to feed whilst we were both asleep (as this is when i produce most), and giving baby a couple of expressed bottles one weekend so that she knew milk could flow faster if she wanted it to, and winding her a lot more. It may or may not work for you and may or may not be practical.