I have a threesome tag on my delicious page (http://previous.delicious.com/bella526) & I'm pretty sure Draco is always the bottom (if not I put a switching warning). Check it out!

Also, the first thing that came to mind with #1 was Harry's Dirty Little Secrets by ChibiDraco (http://chibidraco.livejournal.com/tag/harry%27s%20dirty%20little%20secrets) (has mpreg!Draco), which is a classic.

Also, there is a great protective Charlie (& Ron too eventually) in Barefoot and Wandless by Clucksy (http://archiveofourown.org/works/393974?page=1&view_adult=true&view_full_work=true), which is Charlie/Draco & mpreg...I guess I have a thing for mpreg ;)

I hope this helps! :)