If they already have new jobs that pay the same or more than their old jobs then yes, compensation may be minimal. However, if they are still out of work and it is likely be be a long time before they find other jobs compensation may be significant - 6 months pay, perhaps.
Yes that is possible but unlikely. The tribunal will also look at the ease of getting similar jobs in the area etc so they do not pay out to people who simply do not want to work. There are a lot of factors in play here. I've seen many people look to tribunals to right a wrong and the outcome is rarely the justice they seek.
Rubbish. Employment tribunal cases are decided on the balance of probabilities. In this particular case they don't need to show that they were targeted. Their argument is that it was not a genuine redundancy. As the employer has re-advertised the roles so quickly they (the employer) will have to show that they have valid reasons for re-creating the posts. They may be able to do so but, as it was so quick, they may struggle to convince the court. The fact that they have not contacted the ex-employees to see if they were interested in returning may also count against them.
There has to be proof or reasonable doubt that the employees were targeted. That is hard to prove without evidence. All these guys have to do is say that they trialled what looked to be a great idea and it did not work. If challenged that they targeted them because they raised issues, the employers will say that they were grateful for the prompt and dealt with it accordingly.
There are so many factors in play that we do not know. The person involved, if they are committed to getting a resolution, should seek legal advice. Once all the facts are known, they will be able to make an informed decision.