Most of the points consist about trackables so I'm gonna cover that first - No, I never got into trackables, don't know anything about them so I wouldn't know how to code them
As for the "interested in coding something", I'd be glad to, you would just need to be a little more specific
About the (spiked fiends actually):
I'm pretty sure the quillbeast model would fit perfectly :P
About the skillpoints per level, make it 1 always, and just make a lot of levels that have a minor increase on the ability, I don't think it's too hard to make :P Same for stat points, just with 5.
About the Slow Missiles, there's no such JASS native to slow missiles because there's no such classification "missile". At least not yet. If your missiles are triggered, then use slow missiles to grant the missiles a buff and then when you move those missiles, check if they have that buff. If yes, then offset the distance a little less in the loop.
Gold drops, actually.. not quite what I meant. See in Diablo II there are some key items that grant a good amount of gold when sold. Example - Throwing Knife/Javelin for 480, Class items (depending on the bonuses) can be sold for a lot of gold. The plain gold drops are pretty irrelevant, but I guess you can make it relevant by increasing the amount of gold dropped, not the chance. That won't increase the effort of picking multiple gold coins up. :D
If A and the rightclick are based on the same ability, just restrict the caster from using it in a short amount of time to avoid abusing :P
About the Fallen Shaman elite, no I mean it shouldn't revive other Fallen Shaman -- it was removed quite some time ago because it was waaaaay too annoying. :D
The conclusion text - Yeah if something confuses you or you don't have that much time on you, sure, I can help, but I might be a little pressured by other projects like the two I have now, upcoming contests (and I had another project idea in mind that I will want to start, but I guess it can wait). :P I can't really resist helping so I guess I'm in. :D Idk, if it's ranged then maybe you can use "Attack" order instead of "Smart"? I haven't worked with this stuff yet, so I might be wrong.
I'm really interested in triggering some actual spells from Diablo II, after all I'm both a spell and a DII fanatic!