Some questions about an Aedui campaign

[Famine0]

1. What are hero tombs for? I've never built them since 3000 gold over 8 turns seems a bit much for only +5% happiness. Do they grant heroes certain traits? Also do Helvetii characters gain special bonuses from them (this might be farfetched by me I know )?
2. Do schools give any special traits to characters? I know they grant extra retinue like scribes, geographers, herbalists,.. but the only real trait I've seen is 'Fond of Ribald rhymes'... Also how long can a character benefit from a school, do the benefits keep coming or is it not worth the wait after you've had the first few bonuses?
3. In my campaign I've taken the entire Italian peninsula (overkill maybe), but the people dont semm to like me unless I keep large garrisons in the city. As this is a drain on my treasure is there another way to keep them happy, is there something I'm doing wrong?
4. Is there a way to keep units from throwing their spears before charging? Sometimes I just want my units to countercharge, not throw their spears (and end up taking the charge)...
5. Just out of personal interest: are some tribes better than others (I'm talking about the trait for characters)? My best generals are pretty much always Boii, but alot of the Belgae tribes seem pretty decent too (Bellovaci for example). Do you guys have any personal favorites ? Is there a kind of tribe you always aim for in a campaign?

Thanks in advance :)