When the 'children' have finnished 'fratching'
Orange you are supposed to go here & get or read win98hcl.txt to see whether your hardware is compatible ... for future reference;) - anything not on the list wants removing while you set up everything else (its not 'exhaustive' but shows what 'ought' to be ok).
Turning now to your errant items ...
Wave Device for Voice modem is the part for a speakerphone modem ... its not unusual for this to be 'orphaned' .. you probably have a working driver for the modem, but not all its features - most likely this is 'good'? as a modem but you have this 'strange' bit left, it won't harm ... confirm for me the modem works ! ;)
Creative Soundblaster PCI 128 - I pressume thats what you have but it shouldn't show as just that in sound, video & games controllers, there should also be a game port or midi port showing up ... as you suspect :)... (in fact I think in 98 there maybe ought to be another 'bit too?)
Have we now been to windows update? if not do !