Any way to see if all the panels are connected and working from the voltage or any other number?

I have 10 fitted 5 days ago but i can see the outputs expected (compared to similar system next to me) so I am not doubting myself whether all the panels have been connected or any is faulty.

Any way to check this between having someone in the roof with a tool?

If your system has individual optimizers on each panel you should be able to see the production of each panel. If you have only string optimizers you can see only the total string outputs. I have the individual optimizers on my panels and this is what I can see…per panel.