O.K.,so let me get this straight.You have no alpine or snow hiking experience above 10K, you want to know if you can take the shorter route which bypasses the switchbacks, and you want to know if you can get by without waterproof/ breathable apparel.
So, first off: You need to find out if you get altitude sickness above 10K feet, there is a definate possibility that you may. You have to do prepatory day hikes above 10K to get properly acclimated or you are just setting yourself up for disaster, IMO. If you have no experience with crampons, start learning now. Again, IMO, you have no business on the shortcut without knowing how to use your crampons and ice axe with ease. A male hiker died on the shortcut last year and his wife was moderately injured.
You are going to run into snow on many parts of the trail in late April, in fact probably most of it. You cannot use your summer, canvas light hiker boots for an April ascent. Your feet will be soaked and cold before you can say "under-prepared". It could rain and/or be stormy, so you will need to go prepared. That includes waterproof jackets, pants, boots, 3-4 season tent, 15 degree sleeping bag, and other cold weather gear. The snow may be so soft that you sink up to your hips or it could be so hard you have to use your crampons most of the time.
Our esteemed board member, Bob R, took these fine pictures of his April 30, 2002 ascent.
http://members12.clubphoto.com/robert634908/1286191/guest.phtml Notice all of the snow and water.
Here is Bob's May 2003 ascent.
http://members12.clubphoto.com/robert634908/1310304/guest.phtmlNotice all of the snow and avalanches. Now you get a pretty good idea of what is ahead for you.
Other members can comment on your other questions. But, for my last $.02, do not underestimate the climb, escpecially in April. It is not a straight forward climb like it will be in August. Your not being above 10K feet kinda concerns me.