A few comments from my current experience...

Go with the Gruvenparts water pipe, I tried the eBay one and it did not fit properly, bit the bullet and shelled out for the Gruven version, fits perfectly.

Rear main, I went with the OEM plate with seal already in there...it's a big seal and in my opinion, could be tough to align if you try to do the seal only. It's been done by others to do the seal only (only available aftermarket), but with the amount of effort to get to it, I wasn't willing to take the chance for a couple hundred $$.

Turbo rebuild...I got my Melett CHRA's from https://www.turborebuild.co.uk/turbo-parts.html
Came in about a week and very reasonably priced. Melett seems to be the go-to for rebuilds and CHRA replacements...easy drop-in replacement on these if you are capable enough to do the rest of your project.

Cam tensioner shoes...again, I had to try a few versions...I originally went with the RKX ones since they are a small US based company, but I wasn't happy with them. Ended up going with an eBay version that fit great. Problem on fit that I had was the underside of the shoe where it snaps onto the hydraulic pushrod was somewhat rounded on the RKX, where it should really be squared. The RKX would not seat all the way...they are now seated in the trash can.

Motor mounts, I'm going with the 034 billet version. I originally picked up the 034 street density ones, but decided to go heavier duty. Let me know if you are interested in the street density version and I can make you a deal on mine that I'll be selling. Mainly because I'm powered up and will be throwing manual shifting in there...I think you mentioned on our phone call that you are pretty much stock, so more of an OEM style mount should be fine. You will need the resistors for the sensor plugs if you go 034 so you don't get a code, but cheap on their site and simple to plug in.

Plan on lots of o-rings, gaskets, and nuts/bolts. The turbo studs are stupidly expensive...I think they are about $28 each plus a $7 nut...you'll need 14 of these if you have any issues with them, and really suggested to replace if you are taking apart after so many years. Also, if you pull the cam tensioner shoes, you'll need 52 of the cam cap bolts...cheaper at about $1.10 if you shop around, but it all adds up.

Your efforts will be worth it! Did you ever decide on who you'll have take care of the trans? I have 2 cores for both trans and torque converters if you need them. I know that when we talked, you had spoken with Pat at Level 10...I was impressed with his input, but haven't had any work done, so I'm only going off of his knowledge and enthusiasm from our conversation. On that note, I do have the proper fluid that he suggests if you need it...I bought mine looking ahead, and then decided to go 6 speed.

I have a date with mine this afternoon and all day tomorrow...looking forward to moving forward on my project, and following yours as well! You have my number if you want to call and chat...