I regularly cut about 4kg so about 9lbs for ju-jutsu competitions. I start 4 days before weigh-in. The weight loss is basically all water (nothing new there I think), so the day after the weigh-in I am about 1kg below my starting weight again, the day after that I am back where I started. What I do is what I picked up over time from different people, so nothing really scientific about it just experiences mixed together.
4kg is not as much as you have to do overall and it could be that your starting conditions 4 days till are a little harder than mine because you already lost some water:
Form day 4: I reduce carbs (not to 0 but lower than my regular diet yet enough to keep me sane and going). This is to basically to reduce glycogen which binds excess water. I can't find a source on them but here are some numbers in a wikipedia article on crash diets.
Days 4&3: I drink over 8l of water (0.5l every hour awake + some extra for coffee). So basically what you said some people suggested. I don't know if this is a scientific sound explanation (meaning I don't think so...) but what I heard is that the body gets used to that water intake and will continue loosing more water when you cut supplies. Anyways I tried to watch if it did something to me so I weighted my self before and after each round of water out - water in. I lost about 100g per turn (so about 0.6 out 0.5 in but that method is not very accurate). So to me it seems it forces my body flush out water when there is too much coming in. In short: works for me so i do it. (Watch water poisoning I sometimes get a little dizzy to end of day 3 depending on what I ate still trying to figure that out).
Days 2 and 1 Same as you: reduce water and food. I usually cut enough by Day 2 till so I don't reduce my intake any further.
To the vegetables: It's fruit but I go for fresh pineapple. About 1-2 every day. This might be voodoo but they are said to be further dehydrating and for me they a least don't throw me back but I would try that in a situation where it can't destroy your efforts.
Also since you try to dehydrate a hot bath in a tub is the best way to sweat (after that steam bath then sauna). I did that the evening of 2 days before or the morning of the day before weigh-in when I had to cut more weight. But I don't have a tub anymore :(.
Another thing I never experienced but heard from a lot of people: Don't shower before weigh-in because when dehydrated you skin sucks water. Don't know if it's true or legend but I usually shower and still make the cut.
Edit: Additional info I forgot: The more muscle you have the easier it becomes to cut. So low body fat means that you can cut a higher percentage of your body mass by dehydrating. Thats because there is more water stored in muscles than in body fat.
The alternate tactic I'm currently aiming for is getting my weight down permanently again for next year but I think that's not what you where asking ^^
Edit/Maybe unrelated rant:
I got interested if there was any study relating to the techniques but only found studies looking at the effects of weight cutting for example Acute effects of self-selected regimen of rapid body mass loss in combat sports athletes , Dehydration and acute weight gain in mixed martial arts fighters prior to competitions  or the spread of weight cutting while clustering the methods in general bins like Patterns of weight loss and supplement consumption of male wrestlers in Tehran . Methods where mostly discussed on sites related to weight class sports. Easy to google for example judoinfo.com but generally nothing new.
There was very little on the actual methods mostly general stuff like in :
The reports of the subjects revealed that the RBML was achieved by a
gradual reduction of energy and fluid intake and mild sauna procedures
Why I'm writing this is the following: Most of studies were related to wrestlers and there were some things I didn't know before and I still don't know if I understood this correctly: There are adolescents and even wrestlers below the age of 10 who, in order to cut weight use diuretics and go to sauna in rubber suits ? And it also seems to be common for wrestlers to cut weight for a prolonged time so from what I understood from several news articles and some of the resources I found they don't do this every 2-3 month but during season they cut every week for several weeks during season. Please anyone correct me if I'm wrong because those studies mostly related to high-school and college wrestling in the US and I'm from Germany so I don't know about scheduling of high school wrestling.
Weight cutting means basically cutting your nutritional and fluid intake while trying to stimulate the loss of water to willingly starve and dehydrate yourself to loose a certain amount weight in short time for a very short time. I have no problem with adults willingly doing that to themselves and I've done it to myself without experiencing to bad side effects or diminished performance but I find it perverted to do this to children and adolescents.
Another thing I find scary is that it seems to be pretty common to stimulate sweating by going to the sauna in a rubber or plastic suit. While that on itself is a pretty stupid idea doing this while already dehydrated and weak from fasting is one of the dumbest things I can think of doing to myself without breaking some laws. The idea is basically the same as the 'submerged in a hot tub' method I proposed and find used by most people I know that cut weight by stimulating sweating: If the sweat can't evaporate it has no effect on your body temperature so in its effort to cool you down your body sweats more and it cycles from there. Doing that in a tub or in a steam bath (humidity approaching 100% so sweating has a very limited effect) where you usually won't achieve temperature far above 40 °C (104 °F) without it getting unbearable is one thing but in a sauna with temperatures of 80 and 110 °C (176 and 230 °F) it's just an other way of expressing a death wish.
So while I in no way want to keep adults from weight cutting and find it in my own experience never felt it to be threatening to my life or health (although I thinks it's although not beneficial to health) when done within reason and with a little common sence I would like to express deep concern about some of the practices I found on the web and especially about their application on children and adolescents.
Sorry if this was unrelated to the question but starving and dehydrating children for success in sports is nothing I find acceptable for conscious human beings.