Andronicus, what's all this about improving the brass grab handle??? I thought these were meant to be out of the box builds!!

I wouldn't be embarrassed about it - fixing things that go wrong is all part of it, and though these may be "entry level" kits, the reality is that getting a good result from old or small is just as hard if not harder than getting it from a more expensive, bigger or more recent kit. All that modern slide moulding means you no longer have to drill out your own barrels for example.
I wouldn't try drilling out the wire stump either - agree you should either dig it out, fill the hole and go again from there, or just file it / cut it down with side cutters until flush and then try re-attaching over the same point. Maybe you should just use the kit plastic part!
Washing, I wouldn't use a swab or a cotton bud, but a big very soft paint brush and gently wipe it over with water with a bit of washing up liquid in it, then do it again with clean water. Dry it off in the airing cupboard overnight (I put mine in an old ice cream tub and put it in there near the hot water tank each night to dry off paint and glue as well as water.)
The Johnson's stuff is called Klear in the UK and you can sometimes find it in Robert Dyass, but not that easy to get hold of from what I can tell. I have never done the decal in the wet pool of Klear before, I only coat the model with the Klear, then apply the decals to it when dry (which is about 20 mins) and then apply another coat over to seal them in and remove some of the step effect around them. Obviously you could use varnish for this too, but Klear is miraculously easy to apply compared to varnish (just take care not to stir up bubbles) and quicker drying (so don't keep going back over what you just did as it dries in minutes.)
Maxiplus, really wonderful painting - would you care to reveal your masking technique? Not toothpaste... I see also you have introduced a competitive edge to this, with your contribution of 5!! Grrr...!

I'll have you know I'm not done yet, and what's more I have recruited my 9 year old daughter to the cause...