Do you consider the games linear?

There are a lot of RPGs that are extremely linear, meaning you have to follow a set path and cannot stray from it. These games are all about going from point A to point B. But there are other games that are non-linear, that let you explore at your leisure and trigger events when you want them to happen.

Which category would you place each of the Phantasy Star games into? They may lay out a path for you to follow, but do the games force you to take that path or would you say they give you freedom to explore at your own pace?

Well, let's see...

PS1 has dungeons you don't have to visit.
You can go through the dams and the Dezoris dungeons in PS2 in any order. Plus you you choose you want in your party besides Rolf (and Nei for the first third of the game
PS3 has the different generations of course.
PS4 again has places you don't have to visit plus the guild missions.

I would say they're fairly all open-ended for console RPGs.

Yeah, just about every one of them has some freedom point. In any one of them you can sit and gain levels for hours, for example in PS4 gaining levels fighting in the basement until you get Ryuka, then using it to find out what happens when you teleport out of Piata. Or in PS3 selling you stuff for an escapipe to get out and then the king tells you you can't advance anymore. XD Again in PS4 that popular strategy of them saying Kyra is in danger and you have to hurry and rescue her, then going to every other place in the world and staying at the inn for several weeks on end, then going to save her and everything is fine still.

I think PS3 is very linear. You get to choose the generations, but aside from that everything is laid out very specifically in each one. You can explore a little during the third generation, but it doesn't affect the path of the game.

I would call the others semi-linear. Like Shizzuno listed, there's stuff you can skip and a few parts you can do in different orders, but to complete the overall game you have to follow a linear path at some point. It's not entirely linear, but kind of close to it.