Din cate am citit eu :
Depending on how you stack the triggers (and assuming you control no creatures other than wolfrir), you will be able to draw 5 or 9 cards- not 13.
Zegana's first ability is not a trigger- it is a replacement effect. It will check your creatures before she is on the battlefield. This is before Silverheart's soulbond can even trigger, much less resolve. Silverheart is a 4/4 so she will enter with 4 counters- as a 5/5.
When she enters the battlefield, soulbond and her draw ability will trigger. You control both so you can put them on the stack in any order. Her power is checked on resolution so one of two things will happen:
If you put the soulbond trigger on the stack first, Zeganna's ability will resolve first. At this point she is a 5/5 so you will draw 5 cards.
If you put Zeganna's ability on the stack first, soulbond will resolve first. Pairing her with wolfrir will make her a 9/9. When her ability resolves, you will draw 9 cards.
