358 in a Mauser 98 action is easy. Replace barrel with one for 358 Win
Yes, you can load a little longer or larger/ heavier bullets.
To make a 98 into taking the Winchester Belted mags(264, 300 Win 338Win 458 Win), Remington 7mm Mag, or weatherby standard lengths like 257 WBy or shorter cases like the remingtons 350 or 6.5 or the Marlin 450, the bolt face just needs to be opened the bolt face from .473 ro .530 change the barrel to coraspond to the bullet you want to launch and chamber for that round. You may have to modify the extractor claw a little but not much. I don't think you should have to play with the magizine follower.
But with hand loads or european factory offerings 8X57 can almost equal 358 in bullet weight and I think speeds are greater.
Do not judge the 8X57 on the Remington factory load as it is made for the weakest of the guns chamered in it like the Mauser 88 or the older hunting rifles that were .318 rather then the .323 of today. The Remington 170 grain load is very similar to 30-30 or 300 Savage rather than the 30-06 it is most often compared to.