Tbh, I'd not try Win98 gaming on either of these CPUs. Yes, you can run Win98, but games in 1998 are things like Unreal. With a Pentium MMX, that will give you 11-18fps at low settings. I get that playability back then was judged differently, but this is an unplayable slideshow by anyone's standards, unless you drop to 640x480 or so.
P233MMX would give you decent mid-period Windows 95 performance, but anything from mid 1997 onwards (so before Win98 was launched) will make it sweat badly. I used a P200MMX for my late DOS machine, but decided to upgrade that to a P3-500 to avoid slowdowns. I run Win98SE on a Tualatin P3-1400S, which is slightly overkill, but a late Coppermine P3 is perfectly period-correct for a high-end Win98SE system from just before the launch of XP (I'm assuming WinME or 2k are out of consideration here).
So I'd stick to DOS on this one. In that case the added value of AGP is minimal, so the advantage of the ATX form factor on the PA-2011 might be greater. For DOS, VESA compatibility is more important, so the S3 Trio beats the ATi RageII anyway. As for CPU... at stock there's not much between them, but that P233MMX can almost certainly be clocked to 75MHz FSB, and given the board has three jumpers for FSB yet only has 4 documented speeds, I'm willing to wager you can do more, most likely including 83MHz, which the VP2 chipset can handle and will give you 290MHz.