Recruiting Clive in S2 is easy as pie(It's FAR mroe difficult in S1, where he -randomly- appears in that one town). Completing his sub-quest with Eliza is the part that's hard. As for the Squirrels, they're all secret characters outside of Mukumuku, so it's not -that- bad, since you can look him up with Richmond.
S1 by and large is much harder to fully complete than S2, if only because S2 supplies you with Richmond who tells you how and where to recruit people. S1 only has that cryptic Old Book that tells you that some characters like Pesmerga and Window -exist-, but gives you no clue on how to even begin to find them.