I am renovating a house built in 1874. I have added two spaces for bathrooms one on top of another. The footprint of the baths are aprox 7'- 0" x !5' - 0". The lower bath contains a water closet, lavatory, shower drain. The 2nd floor bath contains a water closet, lavatory, claw foot tub, and a shower drain.

First floor: WC and shower drain on north glass block wall side by side with 3" vent in left north west corner closest to 14" from WC. 2" shower drain is adjacent to right 30" from north glass block wall. 8' opposite from WC is the lavatory which has its own 2" vent to the roof.

Second floor: WC against west wall 7' from 3" vent stack in north west corner. This 3" drain catches the WC and the 2" drain from the lavatory opposite the WC on the east wall. Lavatory stack vents through the roof.

Question: Is the 3" vent in the corner, 2" vent on adjacent wall, and 2" vent on opposite wall enough to vent all the fixtures in the two bathrooms?

It's going to be difficult to answer your question not knowing the underfloor connections. On the first floor bath the only vent that's mentioned is the lavatory vent. I'm assuming the toilet vents through the 3" but is the shower wet vented by the lavatory vent?
Second floor, you mention a "3" drain. This is the toilet drain that discharges into the 3" vent mention in the first floor description? If so the 3" vent from the first floor is now a stack vent instead of a vent stack up to the 3" drain where it then becomes a vent stack on through the roof.
This is acceptable since you apparently are not discharging a major fixture past a unvented minor one.
In short, If your minor fixtures, tub, shower etc. are wet vented through the lavatory roof vents on both floors your vents sound good to go. Good luck, Tom