As seems to be the case with most modern laptops, the T-3400 is standard enough that Linux causes no real trouble. My installation of Slackware 2.1.0 was completely error free, after discounting the flakey memory module.
PCMCIA support was painless to install, and should cause no problems. Beware if you want to use APM and PCMCIA at the same time, you may run into trouble.
XFree86 should also pose no trouble, as long as you are installing version 3.1.2 or later. This version is the first to include support for the WD90C24[A|A2] chipset. Keeping in mind the proviso about using 'Simultaneous' mode for the video hardware, everything should be fine. Note again that I don't have experience on the color machines. Your mileage (as they say) may vary.
Note my disclaimer, since I'm only human, and don't know the details of your hardware...