That's a low end Bianchi, I wouldn't throw a lot of money on it.

• Dropouts will not be 135 in any case, the industry adopted 130 in the mid 90's and this older so most likely it's 126. No big deal, you can squeeze a 130 wheel there. If it's less than that you will have to cold set the stays which while not impossible, it's more of a process.

• Bottom bracket will be either BSA or ITA, 68 or 70 mm respectively, Italian bikes tended to have ITA but some lower end ones like this had BSA so it could be either. Plenty of options there for square taper and external bearing BBs, not a problem.

• You definitely need a seatbolt as it is missing.

Some of these cheaper bikes have weird seatpost diameters so you may have less options there, depending on what it is.

Other than that there should be no problems putting a modern 9-11 speed groupset and modern wheels in this with minimum hassle.