Answers to your problems:

1) Lava power:
Lava power is unquestionably the best solution to get started on power.
~~
Stopping your players from acquiring this power will only resolve to 
create friction, and overall have players dislike the server enough
to not want to play on it. 
Solutions:
a) Make a Lava age(mystcraft), obtain the world border plugin, and then
	chunkload it. Players can then claim their section, and pump from there.
	This requires some upkeep on the staffs part, but that is the staffs 
	job after all. To make things go smoothly with any task given. 
	For even more consistent use of it, save a copy of the age, then
	re upload it every week or so to reset the lava age(and thus the lava).
	Can also world edit the lava back in as well as an alternative. 
b) Create a facility in which lava is sent to multiple tanks from an
	indefinite source, and at the cost of a fee, or donation(if super 
	money hungry) they can get access to one of the tanks. This facility
	would be spot loaded of course(have it all in 1 chunk).
	
2) Loaders:
From what I've come to understand, loaders are a big 'no-no' on this server.
This poses many problems to players. The main issue is for storage purposes,
as well as energy.
~~
Solution: 
Start by forming a new group. This group will be that of regulars/trusted players.
These players can apply for a spot loader to be placed by a staff. It will then be
logged down on a list, and checked every so often to ensure they are following the
regulations of it. 
From what I've learnt, 1 spot loader is just about enough to cover all storage and 
energy needs.


3)Regulars/Trusted
As suggested in topic two, create a new group of trusted/regulars. These are the people
who are to be generally more trusted than the mass of others. The best option I can think
of is that you have your regulars, which are just people who get a couple of special
perks just be being a regular(like multiple homes and such). When I was running the server
the permission list for Members is as follows:
		  Member:
			permissions:
			  essentials.chat.color: true
			  essentials.sleepingignored: true
			  essentials.msg.url: true
			  essentials.chat.url: true
			  essentials.recipe: true
			  essentials.workbench: true
			  essentials.warp: true
			  essentials.warp.list: true
			  essentials.sethome.multiple: true
			  essentials.getpos: true
			inheritance:
			- Novice
This is basically what I'm talking about when I mean regular. Basically a member who just gets
special little bonus's for being them. Since the way you're running the server, you'd probably 
want to take "essentials.warp.list" out of course, but I feel you Understand the principle.
~~
Persons in the trusted group would receive access to items such as the gravi gun, and are able 
to use banned items that bypass protections, but do so in a minimal way. 
Trusted would also be able to place water out side of claims/above ground, after all they are trusted.
This one typically is only given out to people who have applied for trusted and are already a regular.
(apply through the forums of course) 

This gives people a community goal in the game as well as a goal to become trusted. Happier players,
happier server.