Oof, looks like I took too long, I'll post this anyways, just incase.
It's been a while since I've dabbled with good ol' FMCB, buuuut, here is what you want to do, first, get a USB flash drive, make sure it's formatted in the FAT32 format, then, plug that drive into your PS2 usb slot, either or should be fine.
Start your PS2, go into the FMCB browser of some kind, look for the memory card ...
Actually, Pre Edit: I'll just do this in real time so I can give you exact instructions :3...... ......
Ooookay, so... it's a bit more complicated than I thought/remember. You need to have uLaunchELF on your memory card within FMCB, if not, then this won't really help because uLaunchELF is the way to look into the contents of your memory card on your PS2.
I'm not entirely sure how you can install uLaunchELF with just FMCB, there must be a way, but I honestly never had to worry about that stuff because I had someone make my memory card an FMCB one.
If you DON'T have uLaunchELF, then follow this video (super quick google :3) https://www.youtube.com/watch?v=--rACgTx4bI
Once you have that done, you can follow these instructions.
In uLaunchELF, hit O to go into the browser. If your memory card is in slot 1, that means it's MC0 on the screen. Your USB drive on the top slot should be mass.
Go to MC0, do this by having it highlighted/selected and hit O. When you're in, you'll see a lot of folders using the code names for each game, things like BACUS followed by numbers and what not. In each folder should be a single file, the save file of the game, press R1 which brings up a menu, press O on Copy, then hit Triangle a few times to get back to the main screen.
Find mass, hit O again, then hit R1 again and press O on Paste. This should bring up another sub menu. You'll want to select psuPaste, this copies down all the information of the PS2 save file (mcPaste should also work, never use just Paste).
Do that for each of your games and then once you're done, bring your USB drive to your PC. You should be able to see all the files for the save games in them.
If so, you'll need to use a program to open the PCSX2 memory card, mymc is the program that is used for this task, link will be here - scratch that, I'll upload my version that has the missing DLL's needed for the program to work - https://drive.google.com/open?id=0By9ra_...TUxS05GOVU
Now it's a simple matter of opening the program, use mymc gui, when you start it, it'll automagically ask you to locate your PCSX2 memory card, do that and then it should load all the saves in that memory card.
Now just click the import button, locate your saves on the USB drive (or copy them somewhere off the USB drive), and import. I'm not sure if you can import a bunch all at once or if you have to do it one by one, but either way, that should work.
I hope this helps =).