Now that my friends have kids we don't seem to have that much in common anymore.
Now that my friends have all started their families we don't have much to talk about anymore.
1) Now that my friends have kids we don't seem to have that much in common anymore.
「友人たちが子持ちになった今、あまり共通のものがなくなったようだ。」
don't have that much in common で「共通のものを持たない」＝共通の話題や趣味がないなど幅広く共通するものがないと言えます。
2) Now that my friends have all started their families we don't have much to talk about anymore.
「友人たちがみんな過程を持ち始めたから、あまり話題がなくなった。」
don't have much to talk about で「あまり話すことがない」＝「話題がない」「話が合わない」と言えます。
ご参考になれば幸いです！
日本 
