Regarding participant counting, I have a plan which execeeded 120 participants on 1/1/98. there are approx. 18 terminated participants from prior years 3 who we have been unable to locate and subsequently distribute.

Can I hold their balances in a suspense acocutn and avoid having to have an audit and file long form 5500?

Check your plan document; many allow you to forfeit a "lost participant's" account balance if the plan admin. can demonstrate that they have tried to contact the participant (returned envelopes, no response from locating service). The participant's benefit would have to be reinstated (with interest) should they make a claim at a later date.