It would seem the pitch problem is connected to the swash problem.
First of all are the servo arms all at 90 degrees at mid stick? If you can't get them spot on, you may have to resort to sub-trim.
This is vital as any variation will effect the swash level more at extremes of throw.
If the answer is yes, then you should be able to iron out the swash at extremes with the travel adjust. But it can be a fiddly job to get it perfect and it's best to get it right mechanically in the first place.
It's also worth checking all the head linkages and wash out arms etc are all perfectly set up - a loose screw can cause no end of probs.
Regards the pitch changing as you turn the head. Instead of using a spirit level, try using the flybar as a guide. Hold the flybar rigid and level as you do this - I use the blade caddy to hold one paddle parallel to the boom. That way it won't matter if the heli is not perfectly level.
If you have not already, check out Finless Bob's 450 build guide.
He covers everything you could possibly need to know.