the vss output goes to the pcm first so if your trans isnt freaking out its something in or the ground for the cluster. and given the millions of complaints ive read about the cluster and the work trucks we have at work hav ehad to have the cluster replaced i would suspect that. as far as your abs and service air bag you can go to a dealer or a mechanic that has the higher end scanners and see if there are body codes stored and go from there. the o2 needs to be more specific, there are a ton of codes refering to the o2 and only a few would suggest it needs to be replaced, there are circuit codes heater codes, rich or lean codes etc...
1998 Bonneville SSE
2007 Monte Carlo LT-KYB, Clarion, Polk audio, Kicker
1999 Yukon SLE-KYB, Air lift, Reese dual-cam, Tekonsha
1987 Firebird-355/th400-nothing stock