pregulla

Usually 7x50 won't give you wider FoV than 10x50. You get lower magnification but narrower AFoV. Not worth spending 50 pounds on IMO.

I think as a complementary scope to the Mak fast achromat should work fine. At lower powers for DSO CA isn't much of an issue, and for higher powers you already have the Mak. I use 120mm StarTravel as a complementary scope for my 12" Dob and love it for that purpose.

Svbony ED line might be worth a look. 10x42 have great reviews. I have tried Svbony ED 10x50 and they were on par with Bushnell Legacy 10x50 in terms of aberrations across the field, but with better stray light control, better eyecups and better mechanically overall. Being roof design also makes them significantly lighter and smaller.

I would think it won't make much of a difference. Shorter focal length will allow you to reach lower magnifications and wider field. It will make the object brighter but also the sky background, so no much help on visibility. For most object optimal magnification will be within range of your SCT. Smaller central obstruction of reflector over SCT may help somewhat with contrast, then F/6 or slower should theoretically have better contrast, but I am not sure how noticeable will it be in practice.

I was able to register them on ES site. They also perform optically as you would expect from ES eyepieces - sharp almost to the edge and have perfect fit and finish. The astronomy market is too small to set up a line for fake ES eyepieces that would not be obviously fake. Bottom line - I am sure these are genuine.

I have bought quite a lot of stuff from them. Including few ES eyepieces and some miscellaneous stuff. I had a good luck for the most part. One ES eyepiece had a spec on field lens that didn't seem to impact performance and I got a 30% partial refund. Another eyepiece had optical defect and I returned it for a full refund, AliExpress paid the shipping. So there is a risk of getting a QC reject for ES stuff, but on some items the price difference makes up for the risk (some eyepieces I got for less than half of what I would have cost me from EU/US stores). I would first look for sellers that offer free return, not all of them do, then if item is not good you just return it and all you have lost is time.

EQ1 and AZ3 are mounts included with the telescope. OTA is just the telescope, no mount.

Using filter changes focus, so you can't focus and add it later. Maybe you can get a less aggressive filter of same thickness and try using it for focusing.

It all depends on your budget, preferences, observing targets etc. There is no single answer on what should you get. 2" eyepieces offer larger field of view at longer focal lengths, there is no difference in performance in shorter ones. I would suggest adding 2" eyepiece in 30mm+ range, for wide filed low power view and as a finder eyepiece. It also quite different experience compared to stock plossls. There are a lot of options depending on your budget from Panaviews to Naglers. When you don't know what to buy, a zoom + 2x barlow is a good option. It gets you covered until you figure out what your preferences are.

I started by purchasing a low power 2" eyepiece, a zoom and a 2x barlow. That had my needs covered for a while and I didn't feel the urge to add anything else until I figured out what my preferences are. I would recommend something in the 30mm+ range, like PanaView or Aero ED and Hyperflex 7.2-21.5mm zoom. I would also highly recommend getting a red dot (or Rigel/Telrad) + RACI finder. Makes starhopping much more comfortable.

I don't think your eyepieces are the ones to blame. On nights of reasonable seeing I had no problem getting clear views of Cassini division with ES82, or celestron zoom and even stock plossl. Maybe you have been observing when the planets are low above horizon or on nights of poor seeing. Or maybe collimation of your scopes is off

Only above certain focal length 2" eyepieces offer larger field of view. For example if you want 82 degrees apparent field of view than for eyepieces with longer focal length than about 17mm you will need 2", if you want 70 degrees - than roughly above 24mm you need 2". At shorter focal lengths 2" or 1.25" by itself doesn't make a difference.

If only one I would pick a zoom eyepiece. For lunar and planets you want to be able to select magnification based on atmospheric conditions, if you can't have multiple eyepieces zoom would be the best (even if you can, some people still prefer zoom). I use Hyperflex 7.2 - 21.5mm + 2x Barlow for Moon and planets.

I wouldn't recommend either of these 2. 82mm Lightbridge has very fast shperical mirror - which mean it has not so great optical qualitry and very large central obstruction (secondary mirror covering large part of the aperture). CELESTRON SCTW-80 is very short achromatic refractor, it will show a lot of chromatic aberration at higher powers. The Moon will probably be bearable, but the planets will be colorful disks. It also seems to come on photo tripod - winch will make it very shaky and frustrating to use for anything other than lowest powers. If you want to spend minimum amount of money possible I would recommend 70mm F/10 achromat. It will have very little chromatic aberration and will perform much better than the two you have suggested. If you can stretch you budget a little more I would highly recommend getting something like SkyWatcher Heritage 130p or other 130mm table top dob.

I have the 35mm Aero ED and very happy with it in my F/5 scopes. It is not perfect, but for given size and weight (350g) I don't think you can get any better. It is a compromise I am willing to make. I also own ES82 30mm and even though it's better corrected and offers wider AFoV I just don't use it that often because of it's size and weight (over 1kg - almost exactly 3x Aero ED weight) . Another 2" eyepiece in that range I have owned was SW SWA70 32mm and it performed significantly worse at 8" F/6 (what I had back then).