Starting with the tank situation you have to realize that personnel feelings towards friends and such have to be taken out of the equation when dealing in leadership. So it's good you didn't let that get in the way of what needed to be done. However the point I would stress to each is that moral dumps of such kind as overbaring or moodyness can't be tolerated either because if they bring the whole of the raid down then who really wants to be there in the first place. They're just going to get in there do what they have to and leave instead of staying on top of things and working even harder to progress as they would if their spirits are up and actually enjoying the content.
Also one tool that can be used and this goes with the second part as well with the under geared healer... gear is nothing to get in this game anymore to be ready for upper level content. So for instance saying to both tanks something in the lines of "We're friends and thats great but ultimately I have 23 other raiders I've got to worry about so you need to either chill and learn to cooperate or it's going to be to easy to find a replacement. Sorry to say this and all but friends are friends but business is business."
As far as the healers are concerned the one you set out now would take nothing to gear up if that person took it upon themselves to do so. If that person is just waiting for the raids to do it for them then they aren't helping anyone out. No matter how long someone has been with a group it's still their choice to raid and with that comes responsibilities to take it upon themselves to seek out those badges, or pugs, or whatever to achieve the gear neccessary to keep up with current progression. I've got raiders myself who have been with me for 4 years now and since moving into ICC (had the same problem with them in BT in the BC days) they've let their confidence that their places are secure get ahead of themselves and stoped working. So they're now sitting on a reserve list until they get some personnel motivation.
Just whatever you do don't get hung up on the Gear Scores. The skill always will outweigh the gear any day of the week. If they can pull their weigh just fine respect that so long as you see they are trying to gear up more. But if they can pull their weight and still aren't trying then thats not going to work either. Good balance of skill and gear will take you a long way but even great skill can't make you survivable or increase your abilities past the limitations of lower quality gear. You need a good balance of the two.
As always you can find me on US Ysera Horde as the GM of Prevail.