Well, you talk about "reconstruction", and I don't know what "reconstruction" you are referring to, because in your posting examples, standard reconstruction to the hypothetical PIE roots are nowhere to be found.
However you put forward a good observation, about the similarity between Greek and English words, which I agree with:
I fully agree with your explanation, about the differences in sound transformation p----ph----f & d--t, and the conclusion that both languages come from a common mother language. But you are unable to go to the bottom of your analysis, to tell how did that "split" from the "mother language" occur. I am pretty sure, you believe, it was an ancient vernacular language, who naturally descended all the similar lexicon to the daughter languages, in our case English and Greek. What you don't seem to know or accept, is that neither Greek nor English were vernacular language, when they presumably split from the mother language.
English has inherited at least 60% of its lexicon from Latin, which together with Greek, are simply CULTIVATED languages and never been vernacular languages on the first place. How do I know this? Well there are some overwhelming logical indications about this and among them the main one that a language like Ancient Greek which lack syntax, can not be a spoken language, but a written one, whose purpose we know for a fact was created for literacy and liturgical reasons. So, now the question is, what language was used to create the aforementioned Greek & Latin, and all the languages related to them? I don't know if it was 1 or more, but I think they must have used at least a vernacular language of the time, and I strongly believe that was the Albanian language. Even if I use your own examples (1)(2)(3) you will see the connection is through Albanian language, which I know for sure, is a beautiful structure full of onomatopoeic and elementary based structure semantics. Let's have a look:
1. The root of Πους is just Πο like in the English 'paw'. English language differentiate an animal foot from a human one paw--foot. So does Albanian put-(ër)---kamba(këmba). You don't know but so does(did) the Greek : Πους(usually for animals) and ἔμβασις or simply βασις in general.
Like you rightly noticed a sound transformation occurs p-->f(p-ph-f), and from the Albanian put(ër-a modern suffix for the indefinite nouns) goes to the English put~phoot~foot. As for the Greek word, it simply 'transforms' the sound t-->s to acquire the notorious noun suffix 'us', by dropping the sound 't'. The real ancient Greek word ἔμβα-σις is simply the Albanian word (k)ëmba , which self-explain itself: to support, to hold, to base upon.
2.Πορδη .................................Fart , I will add on this equation the Albanian 'pordhë', which happens to be 100 % identical to the Greek Πορδη, because this is an onomatopoeic word, without nationality, created based on the sound of the fart, long before modern Greek nationalism farts, which try to hijack all the past history credits.
3. Yes , you are right, 'tooth' is a structure acquired into English after some sound transformation, of a similar word in another language, but that's not the Greek Oδοντας. Let's have a look. Let's eliminate the vocative adjacent preposition 'o' from Oδοντας--> δοντας. Now let's eliminate the suffix ας. The remaining δοντ is the "real" Greek word. But let me ask you a question: does this part selfexplains, the meaning of the word in Greek. No, like most of the Greek lexicon, which the Greeks use on a daily basis, and don't know the meaning/s. This is not the case for Albanian. The word dhëmb(tosk)-dhonmb(geg)[singular] dhonmbt(plural], takes its meaning from another Albanian word dhëmb=pain, because historically a tooth has been synonymous to the pain.
Now the plural 'dhonmbt' which in Albanian is usually used to name the teeth as a set in singular , was the exact expression used by a common Ancient Greek , in the regular life, until the Church decided to create the language adding in reverse:
(O) + δοντ + (ας). In this process we have sound treatment dhon(mb)t--> o+ dont+as and voila, the new word in a 'new' language, which has been claimed to be the oldest.
