it seems that you are settled on a trip / battlefield control type. i might have another suggestion, but i will save it for after your questions.
trip attack on an AoO...: as you can see from the rules referenced in the links, an AoO is a single melee attack. a trip attack is also a single melee (touch) attack. therefore, you can already do this as is. on a full attack, if you have 3 attacks available, you could attempt to disarm the enemy in front of you for your first attack, throw a dagger at an enemy threatening your ally, and attempt to trip the enemy on the other side of you, all in one round. and if you get just a little bit fancy with your descriptions, it becomes much more cinematic and 'rp'-esque... and therefore, fun.
the spear (with the right feats) can be surprisingly effective at both up close and reach. if you can convince your dm to allow quarterstaff feats to crossover to spear (which, really, they should anyway) it opens up more options.
the bow (with the right options) can be not only a ranged weapon, but also a melee weapon, and even a line attack.
the spiked chain is a really good tactical weapon the way the rules in 3.x are written. that is why it shows up in so many trip-op threads. one may also wish to consider the chain whip if you are allowed to use all official material (ie: non-updated 3.0 stuff) to combine with the lasher for extra fun.
multiclass: it depends on what you want to accomplish. non initiator classes count for 0.5 per level for purposes of selecting ToB options. so a couple of levels of fighter will only drop you one initiator level, and net you two feats, full bab, and good fort saves. it is a viable option if your particular build needs some more feats. ToB classes can hold their own, and be quite fun to describe.
combine actions: a standard action is not compatible with a full attack action in the same round, normally. but see the belt of battle in the MIC. and that simply lets you perform extra actions in the same round which in effect would be = take full attack, then take warblade action. (or warblade action first, then full attack).
suggestions: in reality, the only way to get the players to use tactics, if they are not already doing so, is to have the dm use it on them first, or have other players use it and they see that it works. that is, if the individuals/group in question is capable of tactics. not everyone is good at it - which is important to keep in mind. also, with the numerous options available in 3.x, tactics can be challenging to evolve. after all, it starts with your build options.
but in any case, if the dm has some nps who are good enough to do a ranged disarm, some battle field control, some tripping and/or sundering, some grappling and bull rushing, the party will wise up fast. after all, if the npcs can do it, so can the party. Also, if a player makes good use of it: tripping opponents so that other party members get bonuses to pound on them, grappling an enemy caster to keep them from casting spells, disarm and sunder attempts... the rest of the group will pick up on it. especially if you can fire off snappy (cheese optional) one liners along with the action, even if they are all stolen from books or movies. look for environmental advantages too. swing on stuff. drop marbles on the ground. roll barrels at enemies. drop chandeliers on heads. upend tables. be the fun.
my alternate suggestion: i'm personally fond of a psywar/athasian soulknife/soulbow to give me a mix of manifesting (casting), ranged, and melee options. it is an 80/20 melee/caster type mix. most often the manifesting options are for self buffs. especially if you take the athasian soulknife and soulbow as soon as possible. mix in illumine soul if the campaign is undead heavy.