I'm not all that familiar with the exact compatibilities of cichlids, so someone who actually keeps Cichlids might be better to answer your second question;
but as to your first question - if you want a tropical community tank, then pretty much everything but the Algae Eater will have to be re-homed. There are a few cichlids that are compatible with peaceful fish but neither Convicts nor Jack Dempseys fit into that category.
You could look into Keyhole Cichlids, Kribensis, etc. German Blue Rams (my profile pic) are also nice small community cichlids but they require very clean, very low nitrate water which would probably be a lot of work on that tank.