Welcome and I very much appreciated your post...some super super questions there.
I'll try to answer running down the list.
(1) Diet - despite all the so-called gurus out there, there really is no clinically proven diet that helps lymphedema.
The diet that is best is a generally good diet - right types of food, fruit, meats, carbs etc. It makes absolutely no difference about caffeine. I don't even know where they got that from, except that coffee (caffeine) can act as a diuretic. But, a normal amount is simply not a problem. I love that mug of coffee in the morning and don't see any valid medical reason to not enjot it.
Salt of course may be different. it is generally wise to not use a lot of salt in anyone's diet as they have pretty much shown how an excess of salt can cause significant medical problems anyway. That was a tough one for me because I used to enjoy a little food with my salt. I really really slashed it down when I started the all over lymphedema. Surprisingly, I've done quite well. LOL...ok...amazingly well. I also find that adding a few spices can help on the flavor too. Not pepeprs and stuff that is going to burn you stomach out, but other spices I enjoy...and of course onions and garlic. Fat is also something that we don't need much of so a regular diet with the average amount is just fine.
It frustrates me so much because these wanna be guru's have all these crazy diet ideas and I'll tell you if I had to narrow my diet to what many of these quacks say...yuck...who wants to live/eat like that, especially if there is no need.
The one thing that is critical though is weight control. Obesity and especially morbid obesity can in and of itself cause lymphedema as it literally crushes the lymphatics and overwhelms the system. So, if you are over weight or obese, it is important to loose that weight.
(2) Sports - wearing compression garments and doing exercise is something you'll kinda need to work out for yorself and your situation. Generally, I would simply say that any garment should not cause you pain while doing sports. Neither should the compression bandages. If they do start causing pain, then you'll need to make adjustments, again based on your own lymphedema situation. I am really glad to hear you are getting back into them too. That is going to actually be better for your lymphedema and over all health then just sitting around. Until the disaster of this last couple years I was always very very active and did tons of stuff. Kudos to you on this
(3) Sleeves at night. Again, what I would suggest is having your LE therapist work with you for the correct compression you need. Too loose and yo're right they won't do much good. But, too tight and they can cause other problems such as potentially getting a blood clot. You also don't want them so tight that they bunch up or get twisted in some way.
Because of extensive lung fluid I can't wear any type of compression garment or sleeve and have to stick to bandage wrapping. But, I do know that most other people think their sleeves really help. I would also say be very wise with the use of a pump. You didn't mention the one you use, but compression pumps can cause serious damage and in one study about 35% of the people (male and female) that used it came down with genital lymphedema.
(4) The LympheDivas are the only company I know of that makes more fashionable attire. I've heard you have to be careful about the compression as sometimes it isn't high enough. http://lymphedivas.com/
You might try them. Thing is that they make studd for the ladies and I'm not sure if they make anything for we gents. Hmmm..... a missing market potential here.
Hope this helps Tim. Don't hesitate to post any question or concern and again, a super welcome to the family!
Best to you