Besides adjustable levers there isn't really much other options, not as far as I'm aware of at least.
In regards of the handlebar problem there is a few things that could help.
Take a look at page 4, at the bar clamps there (sadly I can't link directly to the item, but you'll see it)
Some call them raisers. They will raise the handlebar a little bit, but also make the handlebar come further backwards, thus making it closer to you.
Be aware thou, there are ofc other universal ones out there that are cheaper, and would fit on the Rebel, BUT, these and the originals that is one the bike now holds the bracket mounting for your display. A universal pair does not have this. So be aware of that.
As far as I'm aware of the original wires/cables should be long enough when using such risers.
If you need the handlebar even further back, or plan on changing the handlebar to one that is "pointing" more backwards, you will have to get longer wires/cables.
Also be sure that it stears clear of the tank with a full turn.
As for the seat: There has popped up quite a few different options for this now, not difficult to find at all. But be aware of what you're getting and not, since not everything out there is worth it's price, even if it looks nice.
The quality might not always be the best or the safest on some seats.
Hope you're able to make your riding experience more plessant!