1. This has been a greatly contentious issue & greatly misunderstood. Unfortunately just b/c you can't browse somebody does not mean they aren't sharing files. More difficult to browse are non LW clients. Having the chat option enabled seems to greatly enhance browsing others files. You can add the view chat to the colums by right-clicking the column bars in either the main or monitor windows. There you will find that those that have the chat icon are much, much easier to browse. To reiterate just b/c you can't browse doesn't mean they aren't sharing even if they do have the chat option enabled. This is a complex issue & many factors may apply as to why you can't browse them. You should also enable chat. For more on chat & browsing see these:
1. Chat & Browsing (see other links there.) & 2. Enabling Chat & finally 3. Hashing of files & browsing those firewalled

2. Those files listed in red are not presently being shared. When you 1st open LW, all your LW shared files are red. But as LW accounts for them all they one by one turn black. The saved files folder will generally show those files downlded that session as being red. If there's items in your shared folder coloured red then if you press the Refresh button this will force LW re-account for all its files (shouldn't be done too often as it uses up LW's resources doing so.)

3. Hahhaha ... not sure! I've had the same problem & can't explain it. It might be related to the answer in your 1st question. Which is not to say you can't downld from them b/c you definitely can.