Is this place good for groups of 20 to 30?

Tightly, but doable

You could probably get that many in the back. 30 might be a little tight.

The tables there outside seats 4 but you can put those together the tables inside is the same it seats four and then there's tables with two and then there's the bar area a very small place but if you're Seated on the inside everyone will have Separate Tables and I only believe there is only three tables on the right that probably can be pushed together and then on the left around the other side of the bar you can probably do another 3 don't quite think it's a good for a party of 20 to 30 people but is a very nice atmosphere

It can be.

Yes