Absolutely, for method one: Let's say you want to create 50 lineups, and you know you want EXACTLY 5(10%) lineups with James Harden. So you want to create the best Harden lineups. So what I would recommend is calculate 5 lineups with James Harden locked, then in a separate crunch, create 45 lineups with James Harden excluded.
Then you can merge the crunches as shown in this clip:
http://recordit.co/QwmoC954jPFor method two, let's say you want to have a close to even spread of lineups between LeBron, Westbrook and Harden (only one of each in a lineup). What you can do is create a group (under advanced options) with the 3 of them and set the first dropdown menu to "exactly" as shown below:
What this does is forces every lineup to use exactly one of these players. Now, if you set max exposure values of all of these players so that no two of them add up to 100%, but all 3 values must add up to at least 100%, then all 3 will have to be used.
For example you can set them all to 34% but you cannot set them all to 33% because 33 x 3= 99% so you can't account for 100% of the lineups. You can set them all to 49% but not 50% because if you have two of them at 50%, then you aren't forced to use one of them. Also note, these values don't have to be the same, I just did that for simplicity sake. You cannot use 60%, 40%, 30%, but you can use 59%, 40%, 30% because 60+40=100.
The math becomes a lot more annoying the bigger the group gets, and if you choose to use "at least" instead of exactly. So I highly suggest using method 1 because it's far more intuitive and gives the user more control.
Now for uniqueness, this adds the restriction that every lineup produced must be at least x players different from all other lineups produced. This is useful because you don't typically want lineups that are almost identical to each other, but when you have an optimizer with very few restrictions and a very large pool (default lineups), the top lineups can be very similar to each other. This is a feature you definitely want to use if you don't have many restrictions. But if you set it too high, you can run out of lineups really fast.
As for randomness, this just means that between each lineup, the optimizer will move your projections up to the amount you set. So if you set it at 2%, that means it will optimize based on a different set of projections between 98% and 102% of the original projection for EVERY lineup. This adds a little bit of randomness so it may get you away from playing the same stuff as other people, and it can speed up the solves (if you want me to explain why, I can do that, but it's not too important).