I can probably help with this though as I use both those services and am also a 1.0 player.

MistakeNot has the right of it, but further clarification on the 1.0 retainer part is needed - that referred to retainers that players may have hired back in the original version of FFXIV (version 1.0) which is now shutdown and which ARR is a continuation and sequel to. 1.0 players can transfer their 1.0 character data into ARR the first time they play (instead of having to create a new character from scratch), and once they are started in the game, they can rehire their 1.0 retainer immediately (without having to play through the storyline to unlock retainers like normal).

Making a long story short, if a former 1.0 player transfers to a new server in ARR without having rehired their 1.0 retainer first on their original server, they will still be able to do that on their new server and won't lose that ability. That's basically all that means.

Hopefully this is not too confusing.