I was pleased to learn recently that with split crotch pants, you can put a diaper on OVER the pants, and normally the pants stay clean when you potty the toddler or have a miss in the diaper. An important factor in this working is choosing the right material. If you use cotton, even the slightest bit of the pants touching even the slightest bit of the diaper will result in wet pants the instant baby pees, but if you use a fabric suitable for making a diaper cover, like wool or fleece, it will tend to repel the pee. A poop miss may or may not require new pants, depending.
This is really handy now that it is winter. Gwendolyn doesn't want me to set her on the potty anymore, she wants to walk to the potty and sit herself down. This is hard to do with her pants around her ankles, and with regular pants requires the full removal of the pants, and therefore full removal of shoes. Once shoes are off, she quickly removes her socks, thus making the removal of pants, and then re-dressing, quite an ordeal. Removing only the diaper is a lot easier.
What is even easier than that is removing just part of the diaper. I've started making diaper covers that close in front and back, instead of on the sides, to accomplish this. When the front is unsnapped, the straps holding up the back are released and the whole back falls away, but the front is still held up. Thus the diaper is still half on and easy to refasten after pottying. Or the whole thing can be done in reverse to drop the front instead of the back, which I think would work well for babies still using the classic newborn EC hold. Since they close front and back, each position has one snap, so there is only one snap to undo to offer the potty, and redo after.
Additionally, I'm making the covers from fleece and wool, which allows me to use a safety pin to secure the diaper insert, without compromising the long term waterproofing of the cover.
Unfortunately, it doesn't contain explosive liquid poop up the back very well. I don't want elastic around the leg openings, as I don't want my toddler to think it's a diaper now that she has pretty much been diaper trained at daycare, but the design would be improved significantly with underwear elastic added to the waistband front and back.