#1 tip: DON'T AVOID ANYTHING!
I remember my first time going solo I was worried about everything; I was so self-conscious! There is nothing else quite like being a big, burly 20y/o-ish, solo male traveler at Disney to make you feel that way. I avoided certain rides altogether, reluctantly rode others, hid in corners and felt like I was on stage while eating at every restaurant. Sadly I am not exaggerating here. But midway through the trip I just came to the conclusion that I was in it for me and that I shouldn't care what others think. Turns out that nobody did care! Whodda thunk it?
From that first trip, I learned that nothing should be avoided and
everything is worth exploring (at least once) at WDW. I cannot speak on behalf of doing tours solo (yet... my next big adventure will probably consist largely of touring), but I have done everything from room service to signatures, quick service to the Hoop Dee Doo Revue. I ride on Dumbo like I'm 5 years old, sing along with the Country Bears, pay visits to both Figment and Stitch, and even
volunteered as a suit of armor for Belle's Tale

I love exploring the resorts even though I could never afford some of them, I have done the Drinking Around the World.... twice... and not remembered much of it.... twice... I have dressed up for
MNSSHP and stayed awake and partied for the full 24 hours back in May. But through it all have felt like I have grown in my love and appreciation for going solo to Disney and it's all because I don't avoid things; heck I don't think I would want to invite anyone else nowadays because I have so much fun on my own!
But that is the beauty of going solo. You don't (or shouldn't) avoid anything because YOU dictate what all is worth seeing and doing in the first place. I might avoid photo ops, but that's because, quite frankly, I don't like my picture being taken. I might avoid Disney Junior - Live on Stage, but that's only because I have zero desire to see a show about something I have zero interest in (who knows though with such little to do at DHS, I might just check it out). You obviously have the solo lifestyle figured out, and Disney is no exception. You might get the occasional stare or awkward comment (granted I probably shouldn't cry as much as I do at Wishes or laugh as much as I do HDDR or sing as much as I do during CP or Finding Nemo), but I wouldn't have changed anything about my solo trips (the good, the bad, and the ugly). I have loved every single one of them!
I could (obviously) go on much longer here but for the sake of not rambling on, are there specific questions or tips you are looking for? You asked about the signature restaurants vs bars and lounges. If understand you correctly, you are looking for items from the restaurant to be offered at the bars/lounges as like an appetizer or something? I don't think they do that really (some don't offer food, while others offer a fairly limited selection); there might be the occasional overlapping item here or there, but you won't get the same selection I don't think. So honestly, I think it depends on you and what you are looking to get out of those meals. I prefer actually sitting in at those signature restaurants. The dining experiences alone are well worth it and generally, the meals never disappoint. I typically don't drink with my meals (I occasionally pair a beer with it, but I don't like wine and cocktails should be served before/after), but there have been a couple of times I have had a my signature meal and then gone over to the bar/lounge for a night cap. But honestly I would choose a nice meal over a couple of drinks and light appetizers. But again, it depends on you, your stomach, your food preference, your budget and your itinerary (I have taken over 2 hours for signature meals). But I have been to several of the signatures/bars/lounges (and more to come during my Dec trip!). Which ones are you looking at specifically?
In any case, it is definitely exciting that you are testing the waters of going solo to Disney. In my opinion, you have made a
FANTASTIC decision!