The little investigation I did tells me the 88 Camry FWD 3S-FE has 5 insulators (mounts) vs. 4 insulators used on the 88 Camry AWD 3S-FE. The FWD 3S-FE has a center mount that the AWD doesn't. This could be the only difference in the block (the FWD block having tapped holes for this center insulator bracket while the AWD block may not have the tapped holes because no need for the center mount bracket. The other 4 mounts have different part numbers, but similar geometry, which tells me with the AWD setup being heavier, they are just most likely having a harder rubber used to handle the additional weight. The flywheels are also different between the two, but the crankshaft, pistons, bearings, etc., all are the same. I see the transaxle stiffener plate (bolted to the block) is different, but I think it uses the same attaching point to the block. So from an initial blush, I haven't seen anything that tells me there is a block difference between the two that prevents you from using an FWD 3S-FE engine. Given the internals are the same, even if there is a major difference in the block, you could transfer the internals from the better FWD engine to the AWD engine too.
Seeing metallic particles in your oil filter is not a good thing at all.If your filter got plugged with that debris and was bypassing the filter element to keep oil flowing, you may have pump oil with metallic particles throughout the engine, spoiling not only your crank journals, crank and rod bearings, but also your cam bearings (which are not replaceable). If you get that FWD 3S-FE, that head may be used on our AWD 3S-FE block if necessary to give you what you need.
You have a lot of investigation to do. But I would cease driving it immediately to prevent further irreversible engine damage.