Birthday presents for friend's DC...

[pipnchops]

I have an old school friend who has four children aged 12, 10, 8 and a nearly 2yo. We have stayed in touch since school even though our lives took very different directions initially, she has always lived where we went to school and started a family very young while I went away to uni, travelled and eventually now I have moved back to where we grew up and started my own family. I have an 18mo DD. We have become closer again now I've moved back and my DD is a similar age to her 4th child.
I've always sent her DCs birthday cards over the years but not bothered with presents because I didn't really know what kids want and we lived far away for a lot of the time they were growing up. But last year I knew I'd want to get a present for her 4th little one's first birthday and I knew she'd get something for mine, so I got little gifts for the other three as their birthdays came around too. This year I've just got the other three birthday cards again, because I admit I couldn't deal with the hassle and expense of getting silly little gifts... but with her 4th DC's 2nd birthday approaching I'm now panicking because I want to get her something but will that look like favoritism? I'm wishing I'd just kept up getting the others presents! What would you do? I've got myself into a right pickle here!!!