One thing to consider very carefully is who will handle the aircraft. I'm not quite sure what you are saying in your second post but there is a lot of virtue in having your first officer fly the aircraft, especially if the nature of the problem is not 'textbook', and especially if the automatics are compromised. The rationale is that handling the aircraft should be well within their capabilities but if you want a solid diagnosis of a serious problem you want the bloke with the best type/technical knowledge, without distractions. Generally this will be you.
Obviously lots of variable... some types I've flown need you to branch backwards and forwards between checklists for some of the more serious malfunctions. Managing that, along with radio interuptions, is a recipe for a screw up.
So, generally, I tend to give control and the radio to the F/O and then figure out what is going on. In radio terms, your f/o should be able to fight a holding action with ATC if necessary (You can take it back from them once your workload permits and your plan has firmed up enough to advise ATC, until then 'standby' ftw!).
A major priority is to figure out of anything is time critical and get the aircraft pointed in roughly the correct direction. So a 'plan version1' that either (a) points you back for an immediate landing or (b) points you back to the hold for an eventual landing or (c) points you at your takeoff alternate or (d) continues towards your intended destination needs to be made - quickly - and communicated to your f/o. Then just let them get on with it whilst you work the problem.
Checklists, briefing the cabin crew (don't be afraid to give them a warning order - you can always give them a full NITS brief later - a quick "we've got a problem, probably returning to XYZ, don't start the service, I'll call you back with more details when I can" may be golden in terms of getting a secure cabin promptly because otherwise trolleys, cutlery, bags etc will be coming out).
For "continue/return" decisions there will almost certainly be commercial issues so you will probably want to talk to company. I recommend doing this yourself - another good reason to have the f/o take the ATC and the handling, because ultimately its going to be your decision so the f/o will only have to relay to you anyway, might as well talk to the horses mouth.
Obviously in the event of severe handling difficulties you may need to fly yourself, or it could be a team effort (especially with flying control problems), but generally most emergencies can be flown by the f/o. Once you are all set up, you can then take control for the approach and landing, especially if there is anything 'non standard' about it. Your company may require you to land for any malfunction anyway.
But my main point is don't be in a rush to take control. Flying the aircraft is the easy bit, so let the f/o do it whilst you take responsibilty for analysis, planning and communication. The latter tasks are leadship ones which is why they pay you the big bucks (!?).
Just my point of view. Regardless, good luck. Thinking down here pays dividends up there.