In order to hold the wheel steadily at the front, the riser block is quite a neat fit. You might get a tire slightly wider than a road bike tire in there, but a full width Mountain bike tire, I would say probably not.

Yes will take normal fat MTB tyres

I think MTB tyre is able to use on this riser block but it might higher a little bit compare with Road bike tyre.

The block should take all tyre sizes, be aware that you will need a road tyre for the trainer.

You can use moutain bike tyres on trainers but they are a lot noiser. Best to buy yourself a special turbo trainer tyre which would be a lot quieter. Not sure the riser block will take a mountain bike tyre

My bike is a hybrid, but this will be Ok with all tyres.

They would fir but not as well as road tyres, as groves are very slim.

Yes, it is suitable for mtn bike tires also.

2.1 mountain bike wheels don't fully bed into the riser block leaving a space of ~1" underneath the tyre. I don't see a problem with using it like that as the stability is only marginally compromised compared to using a road tyre due to it being seated higher but you might be best checking with the manufacturer. It also means that you may not be able to get totally level compared to your rear wheel axle height.

as far as i'm aware it will accomodate any cycle tyre size - but you need a trainer tyre as the rubber gets hotter than on road