For SS7 choose quality motherboard (and PSU). There's a lot of 'juice' needed on 3.3V line - all PCI and AGP cards. Also AGP implementation is far from perfect on this early boards.
For graphics card I would say - choose the one which is most stable, and have best output signal. If you seek for less blurry signal, probably the best will be ATI (if it is card 'built by ATI', not third party), but less compatible in Windows - no palleted textures nor fog table. According to 'gona compatibility table' it is also less compatible in DOS.
Best compatibility in Windows (from the three) you'll achieve with TNT2, practically speaking in DOS its compatibility is close to 100%. Besides that it has Windows 3.11 drivers 😉
For DOS SB Live is not a very good choice, unless it will be only DOS mode inside Windows 9x.
1) VLSI SCAMP /286@20 /4M /CL-GD5422 /CMI8330
2) i420EX /486DX33 /16M /TGUI9440 /GUS+ALS100+MT32PI
3) i430FX /K6-2@400 /64M /Rage Pro PCI /ES1370+YMF718
4) i440BX /P!!!750 /256M /MX440 /SBLive!
5) iB75 /3470s /4G /HD7750 /HDA