I have Marcel (2.13 lbs.) and Wylie (7.8 lbs.) - and you definitely have to be VERY careful, esp. the first 6-7 mths. after you get them home, with a tinier puppy. We never allowed them to be together in the house unless we were right there with them - bc Wylie could hurt Marcel easily (without intending to at all, of course).
Now that Marcel is 11 mths old, they can stay in areas alone (where there are NO "heights" involved), but we still keep watch if they are on the bed/couch etcetera.
I don't think you can make a wrong decision here. I think the question is whether or not you want to commit to the extra care/caution involved with a tiny. Either way, I'm THRILLED for you!