Bus+Bike+Boeing for Delhi-Manali-Leh-Srinagar-Delhi trip..help please!!

The stuff written here has been mega helpful! I'm toying over the plan of travelling from Delhi to Srinagar and back in ten days from around Sept 1st along with another friend. Here is the very general plan:

Delhi-Manali by overnight bus, spend a night
Manali-Leh on rental bike, 3 day trip, spend 2 nights there
Leh-Srinagar by over night bus, journey time 2D,1N; spend 2 nights
Srinagar-Delhi by Air Deccan flight

Here are a few basic questions that I would like some advice on:

1) Firstly, is this itinerary practically do-able in 10 days? I know its tight but more time is unfo not available, and I really wanna go upto Srinagar and see the place and take the cheap Air Deccan flight back to Delhi! We are a flexible duo and can take a bit of a beating if required!
2) Is it possible to rent bikes ONE WAY ONLY from Manali-Leh and leave them there and carry on with the rest of the tour if the Manali rental place has a branch in Leh or a similar arrangement?
3) I know lots of people have done the bike trip NOT in Enfields, and would like to consider this. Are there rental bikes for this trip that are not Enfileds? Fact is, I've ridden a lotta bikes in India but never an Enfield so I'm not so sure if I can handle it now

Thanks for all the help, I know a few guys on this thread can really gimme some solid advice so pleassse help