There is no investment minimum

I’ve read the technical description of the project, but I still can’t understand if users will be charged any fees or not?

you could look at renting hash.
or i belive there are some coins that only have CPU mining, but IMO laptop cpu wont be able to compute with the Desktop processors on that side too.

You can create any signature, but it will not be the same. Only for level Jr. Member and above will be signatures for the bounty.

Possible: Yes
worth it : No

its X11 coin, you need ASIC's to mine this coin. and with ASIC this coin is hard to mine.

I have received ROI from the pool, post fork. So it seems to be working.

Please take note that your stats on the pool can be a bit confusing.

You can only see your stats while you are actually mining. Furthermore the 360 blocks confirmation time (12-16 hours of mining) creates a delay in your stats which can be confusing. Also the pool pays out 20 ROI per transfer(sometimes a bit more) so if you start mining now, it will take 12-16 hours before your stats even start counting any ROI. As soon as it reaches 20 it will then make a payout. And if you stop mining at this very point, it will keep paying out for another 12-16 hours. The time between payouts is then dependent on your hashrate and the difficulty at the time of mining.

The difficulty changes a lot during a day, so don't expect your payouts to be with the same time interval. It will change during a 24-hour period.

I hope this helped