I was not going to mention the R is proven but here goes.
We know 2nd letter is E. Since MEETING = 1.5, only .5 is left for either --E or ---T, so T is not in the right spot.
Rooting = 1, and T is not in the right spot, so either R is in the right spot or R and T are both in the wrong spot.
If R and T are both valid letters, and there is only 1 E per MEETING = 1.5 and
RECEDES = 3.5 and D is disproven, only 1 E would be allowed, leaving
REC---S, which means all 4 letters are valid with 3 in the right spot in order to have 3.5 score
So RECST would all be valid letters if T is valid. But STORAGE = 1.5, and STRE is too many letters (would equal 2.0 or more), max of 3 can be right for 1.5.
Therefore T is proved not valid. Therefore R must be the first letter.