Question #1: If I burnt a free LR but don't use it (ie it still says Reincarnate on the login screen), can I TR or will that mess something up?

Question #2:
I'd already burnt my free LR, got cold feet and changed my mind, and got close to capping xp for level 18 on my 12 fighter/6 monk. I'm going to be immediately TR'ing him once I hit 20 but I had a build I was considering for my last level.

Right now I'm a light monk that's taken both stuns, cleave, the TWF line, iCrit: Bludg, Imp Sunder, the entire Passage Dragonmark Line, WFocus and WSpec: Unarmed, Power Attack, Quick Draw, Past Life: Monk, and Toughness. Enhancement-wise I maxed out my boosts (haste and versatility), took an extra boost, took all the healing amp I could fit in, maxed out my stun dc's, and took most of the toughness enhancements. I have Kensei II but didn't want to spend the AP for Shintao I yet.

I'm considering adding more durability by dropping the dragonmarks (3 feats), weapon focus, weapon spec, and quick draw to add Combat Expertise, Dodge, Mobility, Spring Attack, Whirlwind, and Skill Focus: UMD (I'm in that ugly spot where two item swaps gets me to the 34'ish range - those extra points would be huge). Then I would go Stalwart Defender II instead of Kensai II. I'd be giving up 2 points on my stuns (4 when Power Surge is running) but adding a ton more survivability. One big question I have though is on AC. Am I going to be able to do anything meaningful for Heroic Elites with AC on a primarily Str-based toon (14 base dex and 14 base wis)? I'd be in SDII's stance and earth stance both so that would help quite a bit...just not sure if it's enough to warrant worrying about AC or if the survivability of the new build is enough to warrant what I lose in tactics, boosts, and damage. Lastly, if I'm building this toon to solo heroic elites w/ or without a hireling depending on the content would I be better off as light or dark? I can see the value of both the healing curse from light and the incorporeality from dark.

I'm not decided on changing anything - I really like the current build but it's fairly squishy with only the PRR from earth stance and no meaningful AC. But I'd love to be able to solo elites or even hards without burning through tons of consumables or constantly worrying that my hireling is going to get killed. If SDII would work better for that on those last few levels I'd definitely take a look at it.