The eventual plan surrounding 150207 is that...
It will be re-split into two 150/2 Vehicles again, and these will be inserted into 150121 & 150127 for use in the Bristol area - This releasing the 2 x 153s...
But, this will take place after the ex LM 150s have been refreshed, So until then, they will be split and reformed into 153397 & 153398
As for 150001 & 002, Newtonmgr covered what i knew of on the London Midland Class 150 Farewell thread:
Newtonmgr
124 left LM last night. 106 staying until 107 fixed (needs new engine) but should be off in next fortnight. 150001 & 125 staying until Jan apparently as 172222 & 331 will not be delivered until new year as awaiting parts!. Possibility of 001 staying until March to cover Hfd diagram whilst 105/7 & 9 are refreshed. Rumour LM want to keep it but unlikely to happen if FGW have them. If the scuds take over Rdg-Bas won't be until next May as crew training will need to take place which will take place using 002 probably in new year giving time for that to be turned into FGW colours with 001 being done in April maybe.
So in other words, 150001 could be staying with LM for a few more months, whilst 002 will be refreshed, and crew training taking place (Apparently due imminently!)...Then, as soon as 001 is released, that will be refreshed and enter service with FGW... All before the May timetable next year, although i gather there could be a chance of 002 entering service before next May!