or, your interpretation could simply be that JIm wanted harry and bob out of the house while the fixing was done.
there is, at that time period, a secret door into the basement that harry did not know of, but that lea and mab did; furthermore, it is one they both had keys too.
and as tot he discussion about looking at the books individually or as a whole; to solve your mystery you are also looking at it as a whole- just tkaing one puzzle piece and then speculating from there without referncing any other books still requires refernecing other books.
for example, the discussion about time travel requires referncing wojs about future books that have not even been written yet; the assumption that 'thomas let some else in' requires an entire chain of specualtions without any woj whatsoever- as there is no one, I am aware of, in woj or written books that implies any conection between thomas and the gatekeeper.
-any connection between thomas and eb isnt confirmed until GS, much later, again a conection from outside PG. so youre going to have to build your specualtion chain.
-as to the car, im not saying it does have anything to do with LC. persoanlly, i doubt it. but its just as likely as harry stepping outside to do so- both got harry out of the house for a while; and unlike his just stepping out at least if your suspect hit him with the car theyd know hed be out of the house for a while, and stay there.
id assume that fixing LC took time, and a fair amount of care. I would want to make sure harry was going to be gone and stay gone for a while.
(which is why i always figured mab did it when they were asleep.)
but again, getting past thomas is no more easy than getting past harrys wards. for any of your suspects, its almost cetainly harder:
future harry could just unlock the wards
future molly could as well
Elaine could probably pick the wards more easily than talking her way past thomas
(she has before)
Eb was busy
futue maggir jr? shell be what, 13 when book 19 rolls around?
The gatekeeper? the assumption going for him is that he is a super good wizard with precog abbillities and divination skills that can not only foresee that the table will be needed, is flawed, can fix it, but cant pick the locks on harrys wards, but despite being a seven foot tall wizard whom thomas has never met, not a friend of harrys, can still talk his way past thomas, fix things, and get thomas not to talk in under an hour or two?
ok, i see one way. justine had a rather miraculous recovery after BR. if it turns out the gatekeeper contact thomas before hand, and cut some cort of deal with thomas for justine's health, ill buy it.
or if someone can think of something equivalent.
so.. the hallmark of a good theory is that it predicts things, and is later proven corect ( my mab thoery predicted the end of GS, and was pretty darn close. even tho i wrote it several years before.)
ergo.. what the prediction for a thomas/justine/ gatekeeper theory?
best I can think of is : inn the next few books, justine meats the gatekeeper and recognizes him. or mentions a magiacl healing potion thomas found for her..